CBSE EXAMINATION PAPER-2013
NEET-ZOOLOGY
(Solved)
General Instructions :
Read the following instructions carefully and follow them :
- This question paper contains 180 questions. All questions are compulsory.
- This question paper is divided into 1 sections.
- Section A – questions number 1 to 180 are multiple choice questions
- There is no overall choice given in the question paper. However, an internal choice has been provided in few questions.
- Use of calculator is NOT allowed.
Section A
The plant body is thalloid in
The plant body of a liverwort is haploid (n), gametophytic, small, dorsoventrally flattened, thallose, dichotomously branched fixed by unicellular and unbranched rhizoids, e.g., Marchantia.
Specialized cells for fixing atmospheric nitrogen in Nostoc are
Heterocysts are large sized, thick-walled specialised cells which occur in terminal, intercalary or lateral position in filamentous cyanobacteria, e.g., Nostoc. They have enzyme nitrogenase and specialised to perform biological nitrogen fixation.
The common characteristics between tomato and potato will be maximum at the level of their
Families are characterised on the basis of both vegetative and reproductive features of plant species. Tomato (Lycopersicon esculentum) and potato (Solanum tuberosum) belong to the same family Solanaceae.
What is common in all the three, Funaria, Dryopteris and Ginkgo?
The female sex organ archegonium is formed in bryophytes (Funaria), pteridophytes (Dryopteris) and gymnosperms (Ginkgo).
The pair of quantities having same dimensions is
Work = Force × displacement
= [MLT⁻²][L]
= [ML²T⁻²]
Torque = Force × force arm
= mass × acceleration × length
= [M] × [LT⁻²] × [L] = [ML²T⁻²]
The displacement 'x' (in meter) of a particle of mass 'm' (in kg) moving in one dimension under the action of a force is related to time 't' (in sec) by t = √x + 3. The displacement of the particle when its velocity is zero, will be
∴ t = √x + 3
⇒ √x = t − 3 ⇒ x = (t − 3)² ...(i)
v= dx/dt = 2(t-3)=0
⇒ t = 3
From equation (i),
∴ x = (3 − 3)²
⇒ x = 0
Which one of the following is wrongly matched?
Cyanobacteria, e.g., Nostoc, grow in such abundance as to form water blooms. Sargassum belongs to brown algae which possess chl a, c, carotenoids, xanthophyll and a characteristic brown pigment, fucoxanthin. Commonly known forms of basidiomycetes are mushrooms, bracket fungi or puffballs. In Spirogyra gametes are non flagellated (non-motile) but similar in size. They show amoeboid movements.
Among flowers of Calotropis, tulip, Sesbania, Asparagus, Colchicine, Sweet pea, Petunia, Indigofera, Mustard, Soyabean, Tobacco and groundnut how many plants have corolla with valvate aestivation?
Calotropis, tulip, Asparagus, colchicine, Petunia, mustard, tobacco having valvate aestivation while sweet pea, groundnut, soyabean, Indigofera, Sesbania having vexillary aestivation.
How many plants among China rose, Ocimum, sunflower, mustard, Alstonia, guava, Calotropis and Nerium (Oleander) have opposite phyllotaxy?
Phyllotaxy is the pattern of arrangement of leaves on the stem or branch.
Ocimum, Guava, Calotropis → Opposite phyllotaxy
China rose, Sunflower, Mustard → Alternate phyllotaxy
Alstonia, Nerium (Oleander) → Whorled phyllotaxy
Which of the following statements is not true for stomatal apparatus?
Sometimes, a few epidermal cells in the vicinity of the guard cells become specialised in their shape and size and are known as subsidiary cells or accessory cells.
Meristematic tissue responsible for increase in girth of tree trunk is
Lateral meristems are meristems which occur parallel to the circumference of the organs in which they develop. They undergo periclinal divisions producing secondary tissues on the outer and inner sides and increase girth of the plant organs. Examples are vascular cambium and cork‑cambium.
Inflorescence is racemose in
Inflorescence in family Fabaceae (e.g., soybean) → Racemose
Inflorescence in family Liliaceae (e.g., tulip, Aloe) → Solitary/cymose; often umbellate
Inflorescence in family Solanaceae (e.g., brinjal) → Solitary, axillary or cymose as in Solanum
During the metaphase stage of mitosis spindle fibres attach to chromosomes at
Kinetochores are small disc‑shaped structures at the surface of the centromeres which serve as the sites of attachment of spindle fibres to the chromosomes that are moved into position at the centre of the cell. Hence, metaphase is characterised by all the chromosomes coming to lie at the equator.
Uridine, present only in RNA is a
The combination of pentose sugar with nitrogenous bases (purines or pyrimidines) is called nucleoside. Examples: adenosine, guanosine, cytidine, thymidine, uridine.
The term ‘glycocalyx’ is used for
Glycocalyx or mucilage is the outermost coating of
bacterial cells/cell wall which is rich in polysaccharides. A thick and tougher mucilage is called capsule which gives gummy or sticky trait to cells. It protects the cells from dessication, toxins and preventing attachment to foreign invaders.
Vectors 𝐀⃗ 𝐁⃗ and 𝐂⃗ are such that: 𝐀⃗ 𝐁⃗ = 0 and 𝐀⃗ .𝐂⃗ = 0. Then the vector parallel to 𝐀⃗ is.
Vector triple product
𝐀⃗ x (𝐁⃗ x 𝐂⃗) = 𝐁⃗ ( 𝐀⃗ .𝐂⃗)- 𝐂⃗ (𝐀⃗ .𝐁⃗)=0
⇒𝐀⃗ || (𝐁⃗ x 𝐂⃗)
Which of the following type of plastids does not contain stored food material?
Chromoplasts are non-photosynthetic coloured plastides which synthesise and stored carotenoid pigmentes. They, therefore, appear orange red and yellow where as amyloplast (store starch), aleuroplast store proteins) and elaioplast (store oil droplets and fats) are leucoplasts, colourless plastids.
A car is moving in a circular horizontal track of radius 10 m with a constant speed of 10 m/s. A bob is suspended from the roof of the car by a light wire of length 1.0 m. The angle made by the wire with the vertical is
Given: speed = 10 m/s; radius r = 10 m
Angle made by the wire with the vertical is θ.
Then,
T cos θ = mg
T sin θ = mv²/r
So,
tanθ = v²/rg = 10²/10x 10 = 1
⇒ θ = 45° = π/4
During meiosis I, the chromosomes start pairing at
During zygotene, a substage of Prophase Ⅰ of meiosis Ⅰ, chromosomes start pairing together called synapsis. Such paired chromosomes are called as homologous chromosomes. A complex structure i.e., synaptonemal complex is formed by a pair of synapsed ‘homologous chromosomes called a bivalent or a tetrad.
A person holding a rifle (mass of person and rifle together is 100 kg) stands on a smooth surface and fires 10 shots horizontally. If each bullet has a mass of 10 g with a muzzle velocity of 800 m s⁻¹. The final velocity acquired by the person and the average force exerted on the person are
According to law of conservation of momentum
MV + mnv = 0
⇒ V = -mNv/M = -(0.01 kg × 10 × 800 m/s)/100
⇒ -0.8 m/s
According to work energy theorem,
Average work done = Change in average kinetic energy
i.e., Fₐᵥ × Sₐᵥ = ½mV²ᵣₘₛ
⇒ (FₐᵥVₘₐₓt)/2 = ½m(V²ᵣₘₛ/2)
⇒ Fₐᵥ = 8 N
Which two distinct microbial processes are responsible for the release of fixed nitrogen as dinitrogen gas (N₂) to the atmosphere?
In the global nitrogen cycle, bacterial denitrification is recognised as an important process that converts fixed nitrogen to atmospheric nitrogen gas (N₂). In the marine nitrogen cycle, anaerobic oxidation of ammonium coupled to nitrate reduction contributes substantially to N₂‑production in marine sediments.
A particle with total energy E is moving in a potential energy region U(x). Motion of the particle is restricted to the region where
As the particle is moving in a potential energy region.
∴ Kinetic energy > 0
And, total energy E = K.E. + P.E.
⇒ U(x) <E
One coolie takes 1 minute to raise a suitcase through a height of 2 m but the second coolie takes 30 s to raise the same suitcase to the same height. The powers of two coolies are in the ratio of
∵ Power P = W/t
⇒ P₁/P₂ = t₂/t₁ = 30 s/1 minute = 30 s/60 s = 1/2
(t₁ = 1 minute; t₂ = 30 second given)
Which of the following best illustrates FEEDBACK in development?
During embryonic development, the primary organiser signals the development of another organ or tissue by secreting chemical factors.
The viability of seeds is tested by
Dehydrogenase enzymes present in living tissue reduce the tetrazolium chloride to formazan, a reddish,water insoluble compound. This reaction occurs in or near living cells which are releasing hydrogen in respiration processes. Viable tissues produce a normal red-colour, weak Jiving tissue produce an abnormal colour. Dead tissues do not stain, remaining usually white.
Two discs are rotating about their axes, normal to the discs and passing through the centres of the discs. Disc D₁ has 2 kg mass and 0.2 m radius initially angular velocity of 50 rad s⁻¹. Disc D₂ has 4 kg mass, 0.1 m radius and initial angular velocity of 200 rad s⁻¹. The two discs are brought in contact due to face, with their axes of rotation coincident. The final angular velocity (in rad s⁻¹) of the system is
Given: m₁ = 2 kg ; m₂ = 4 kg
r₁ = 0.2 m ; r₂ = 0.1 m
ω₁ = 50 rad s⁻¹ ; ω₂ = 200 rad s⁻¹
As, angular momentum,
I₁ω₁ + I₂ω₂ = (I₁ + I₂)ω
∴ ω_f = (I₁ω₁ + I₂ω₂)/(I₁ + I₂)
= (½m₁r₁²ω₁ + ½m₂r₂²ω₂)/(½m₁r₁² + ½m₂r₂²)
By putting the value of m₁, m₂, r₁, r₂ and solving we get
100 rad s⁻¹
The radius of the earth is R and the radius of earth. Both have almost equal average mass-density. If Vₚ and V_E are escape velocities of the planet and the earth, respectively, then
Escape velocity,
Vₑ = √(2GM_E/R_E)
= √2G/ R_E (4/3 πR_E³ρ_E) = R√(8/3 πGρ_E)
⇒ Vₑ ∝ Rₑ ⇒ Vₚ/V_E = Rₚ/R_E = 2
⇒ Vₚ = 2V_E
A particle of mass m is kept at rest at a height 3R from the surface of earth, where R is radius of earth and M is mass of earth. The minimum speed with which it should be projected, so that it does not return back, is (g is acceleration due to gravity on the surface of earth)
As we know, the minimum speed with which a body is projected so that it does not return back is called escape speed.
Vₑ = √2GM/r = √2GM/ R +h = √2GM/4R
= (GN/2R)¹ᐟ² (∵ h = 3R)
The pineapple which under natural conditions is difficult to blossom has been made to produce fruits throughout the year by application of
Plants which are difficult to flower can be made to do so by spraying them with 2,4,-D (2,4 dichlorophenoxy acetic acid) and NAA (napthalene acetic acid) which are synthetic auxins, e.g, litchi, pineapple.
Which of the following elements is a constituent of biotin?
Biotin, also known as vitamin H, is a water-soluble B-vitamin. It is a coenzyme for carboxylase enzymes, involved in the synthesis of fatty acids, isoleucine, valine and in gluconeogenesis. Sulphur is a constituent of biotin.
Bundle sheath cells
In C₄ plants, bundle sheath cells are rich in RuBisCO, but lack PEPcase. The CO₂ released in the bundle sheath cells enters the C₃ or the Calvin pathway, common to all plants. Thus, the basic pathway that results in the formation of sugars, the calvin pathway is common to the C₃ and C₄ plants.
Which one of the following statements is correct?
Cleistogamous flowers do not expose their reproductive parts. Anthers and stigma lie close to each other. Pure autogamy occurs since there is no chance of cross‑pollination. Cleistogamy is the most efficient floral adaptation for promoting self‑pollination. E.g., Viola mirabilis and Oxalis autoseila.
Megaspores are produced from the megaspore mother cells after
Single Megaspore Mother Cell (MMC) with dense cytoplasm and a prominent nucleus gets differentiated from nucellus near the micropylar region. This Megaspore Mother Cell (MMC) undergoes meiosis to form ‘4’ haploid cells called megaspores and the process of formation is known as megasporogenesis.
Syngamy can occur outside the body of the organism in
In most aquatic organisms, such as a majority of algae and fishes as well as amphibians, syngamy occurs in the external medium (water), i.e., outside the body of the organism. This type of gametic fusion is called external fertilisation.
Animal vectors are required for pollination in
There are different types of vectors involved in pollination. For example, Maize, mulberry → pollination by wind. Vallisneria → pollination through water (hydrophily). Cucumber → Bees are brought for the commercial plantings of cucumber.
If the ratio of diameters, lengths and Young's modulus of steel and copper wires shown in the figure are p, q and s respectively, then the corresponding ratio of increase in their lengths would be
From formula,
Increase in length,
ΔL = FL/AY = 4FL/(πD²Y)
ΔLₛ/ΔL_c = (Fₛ/F_c)(D_c/Dₛ)²(Y_c/Yₛ)
= 7/5 × (1/p)² × (1/5)⁴
= 7q/(5p²)
Which of the following statements is correct?
Pollen grains are generally spherical and have a prominent two‑layered wall. The hard outer layer called the exine is made up of sporopollenin, one of the most resistant organic materials known. It can withstand high temperatures and strong acids and alkali.
Albuminous seeds store their reserve food mainly in
Endosperm is the nutritive tissue which provides nourishment to the embryo in seed plants. Albuminous seeds retain a part of endosperm as it is not completely used up during embryo development (e.g., wheat, maize, barley, castor, sunflower).
Random unidirectional change in allele frequencies that occurs by chance in all populations and especially in small populations is known as
Genetic drift is random change in allele number and frequency in a gene pool due to chance (e.g., small population size). It is caused by sampling error in the gene pool forming the next generation. The sampling gene pool is generally small in size, limiting variability.
A fluid is in streamline flow across a ‘horizontal pipe of variable area of cross section. For this which of the following statements is correct?
According to Bernoulli's theorem,
p + 1/2 ρv² = constant and Av = constant
If A is minimum, v is maximum, P is minimum.
The density of water at 20°C is 998 kg/m³ and at 40°C is 992 kg/m³. The coefficient of volume expansion of water is
T₁ = 20°C; T₂ = 40°C
ρ₂₀ = 998 kg/m³; ρ₄₀ = 992 kg/m³
As ρ_T₂ = ρ_T₁ / 1 + γ∆T =ρ_T₁/1+ γ(T₂ − T₁)
∴ 992 = 998 / 1 + γ(40 − 20) ⇒ 992 = 998 / 1 + 20γ
⇒ 20γ = 998/992 − 1 = 6/992
⇒ γ = 6/992 ×1/20 = 3 × 10⁻⁴ /°C
Two metal rods 1 and 2 of same lengths have same temperature difference across their ends. Their thermal conductivities are K₁ and K₂ and cross-sectional areas A₁ and A₂, respectively. If the rate of heat conduction in rod 1 is four times that in rod 2, then
Q₁ = 4Q₂ (Given)
⇒ K₁A₁Δt/L = 4.K₂A₂Δt/L⇒ K₁A₁ = 4K₂A₂
Which of the following is not a property of the genetic code?
Genetic code is the relationship of amino acid sequence in a polypeptide and nucleotide/base sequence in mRNA/antisense strand of DNA. It is universal, i.e., a codon specifies the same amino acid in all organisms, non-overlapping, i.e., adjacent codons are independent with no base being member of two codons, degeneracy, i.e., some amino acids are coded by more than one codon, hence the code is degenerate, unambiguous, i.e., one codon codes for only one amino acid.
Genetic variation in a population arises due to
Crossing over leads to recombination of genetic material on two chromosomes. Mutation alters DNA sequences, changing genotype and phenotype. Along with recombination, mutation introduces variation in DNA.
Satellite RNAs are present in some
Plant viruses often contain parasites of their own, referred to as satellites. Satellite RNAs are dependent on their associated (helper) virus for both replication
and encapsidation. Example—Tobacco Necrosis Virus (TNV). Viroids are infectious agents smaller than viruses. Bacteriophages are viruses that infect the ‘bacteria. A prion is an infectious agent that is composed primarily of protein.
A system is shown in the figure to a state c by two paths adc and abc. The internal energy at a is Uₐ = 10 J. Along the path adc the system absorbs δQ₁ = 50 J and the work done is δW₁ = 20 J, whereas along the path abc the heat absorbed is Q₂ = 36 J. The amount of work done along the path abc is
From first law of thermodynamics
Q_adc = ΔU_adc + W_adc
50 J = ΔU_adc + 20 J
ΔU_adc = 30 J
Again,
Q_abc = ΔU_abc + W_abc
W_abc = Q_abc − ΔU_abc
= Q_abc − ΔU_adc
= 36 J − 30 J
= 6 J
One of the most frequently used techniques in DNA fingerprinting is
The technique of DNA fingerprinting was developed by Dr. Alec Jeffrey in 1984. It is a technique generally using repeated sequences (repetitive DNA) in the human genome that produces a pattern of band that is unique for every individuals. These short nucleotide repeats vary in number from person to person and are called variable number of tandem repeat (VNTR). VNTR belongs to class of satellite DNA referred to as minisatellite.
Which one of the following vectors is used to replace the defective gene in gene therapy?
Adenovirus is non‑enveloped dsDNA virus which cause respiratory diseases. Adenovirus is used as a vehicle to administer targeted therapy in the form of recombinant DNA or protein. Specific modifications on fibre proteins are used to target adenovirus to certain cell types, a major effort is made to limit hepatotoxicity and prevent multiple organ failure.
Which of the following relations does not give the equation of an adiabatic process, where terms have their usual meaning?
Adiabatic equations of state are
PVᵞ = constant TVᵞ⁻¹ = constant
P¹⁻ᵞTᵞ = constant
Which of the following statements is not true about somatic embryogenesis?
Somatic embryogenesis is a process where a plant or embryo is derived from a single somatic cell or group of somatic cells. Somatic embryos are formed from plant cells that are not normally involved in the development of embryos, i.e., ordinary plant tissue. No endosperm or seed coat is formed around a somatic embryo.
Genes of interest can be selected from a genomic library by using
A hybridization probe is a fragment of DNA of variable length which is used in DNA samples to detect the presence of nucleotide sequence (the DNA target) that are complementary to the sequence in the probe. The probe hybridize to single‑stranded DNA whose base sequence allow probe target base‑pairing due to complementarity between the probe and target.
During the process of isolation of DNA, chilled ethanol is added to
Ethanol is non‑polar molecule while DNA is a polar molecule, it has a net negative charge due to the phosphate groups attached to it. When DNA is placed in a solution of 100% ethanol, it becomes insoluble and precipitates out of solution.
RNA interference involves
RNA is a method of cellular defense in all eukaryotes. It is a system within living cells that helps to control the activity of specific genes. This method involves silencing of mRNA due to complementary double stranded RNA that prevents translation of target gene or mRNA [silencing]. Source of ds RNA is retrovirus (having RNA genome) or transposons (mobile genetic material).
Benthic organisms are affected most by
The sediment characteristics often determine the type of benthic animals that can thrive there.
Which of the following has maximum genetic diversity in India?
During the period 1960 to 2000 rice production went up from 35 million tonnes to 89.5 million tonnes. This was due to the development of semi-dwarf varieties of rice. There are 2,00,000 varieties of rice in India.
Which organization publishes the Red Data Book?
IUCN or WCN maintains a red data book which is a catalogue of threatened plants and animals facing risk of extinction. The IUCN red list (2004) documents the extinction of 784 species (including 338 vertebrates, 359 invertebrates and 87 plants) in the last 500 years.
The largest tiger reserve in India is
Nagarjunasagar‑Srisailam Tiger Reserve is the largest Tiger reserve in India and the only Tiger Reserve in Andhra Pradesh state.
The second commitment period for Kyoto Protocol was decided at
The Kyoto Protocol is an international agreement linked to the United Nations Framework Convention on climate change which commits its parties by setting internationally binding emissions reduction targets. In Doha, Qatar on 8 December 2012, the “Doha Amendment to the Kyoto Protocol” was adopted. The second commitment period was from 1st Jan, 2013 to 31st Dec. 2020.
Which one of the following is a primary consumer in maize field ecosystem?
In an ecosystem, producers (e.g., plants/phytoplankton) belong to first trophic level, herbivores or primary consumer (e.g., grasshopper) to the second and carnivores or secondary consumer (e.g., lion, wolf) to the third trophic level.
The characteristics of class Reptilia are :
In option (a) all the characteristics belong to class Reptilia. In options (b), (c) and (d) the characteristics belong to the classes Amphibia, Osteichthyes and Chondrichthyes respectively.
Two Carnot engines A and B are operated in series. The engine A receives heat from the source at temperature T₁ and rejects heat to the sink at temperature T. The second engine B receives the heat at temperature T and rejects it to the sink at temperature T₂. For what value of T are the efficiencies of the two engines equal?
Efficiency of engine A, η₁ = 1 − T/T₁
Efficiency of engine B, η₂ = 1 − T₂/T
Here, η₁ = η₂
∴ T/T₁ = T₂/T ⇒ T = √(T₁T₂)
In a vessel, the gas is at a pressure P. If the mass of all the molecules is halved and their speed is doubled, then the resultant pressure will be
∵ P = 1/3.mN/V.v²ᵣₘₛ
where
m = mass of each molecule
N = total number of molecules
V = volume of the gas
When mass is halved and speed is doubled then
Resultant pressure, P' = 1/3 x (m/2) x N/V (2vᵣₘₛ)²
= 2P
Which one of the following animals is correctly matched with its one characteristic and the taxon?
Animal | Characteristic | Taxon |
|---|---|---|
(a) Duckbilled platypus | Oviparous | Mammalian |
(b) Millipede | Ventral nerve cord | Arachnida |
(c) Sea Anemone | Triploblastic | Cnidaria |
(d) Silverfish | Pectoral and Pelvic fins | Chordata |
Duckbilled platypus is oviparous and comes under phylum mammalia. Millipede belongs to the phylum arthropoda. Sea‑anemone is diploblastic belongs to phylum cnidaria. Silver‑fish is an insect belongs to phylum arthropoda, having long antennae, no wings and move in a wriggling motion that resembles the movement of a fish.
Which one of the following groups of animals reproduces only by sexual means?
In Ctenophora, sexes are not separate. Reproduction takes place only by sexual means. In Cnidaria, which exist in both forms, polyps produce medusae asexually and medusae form the polyps sexually. Porifera (sponge) reproduce asexually by fragmentation and sexually by formation of gametes. Protozoans come under protista which reproduce asexually and sexually by cell fusion and zygote formation.
Sharks and dogfishes differ from skates and rays by
Sharks and dogfishes have cylindrical body while skates and rays have flattened body with winglike pectoral fins which are not distinct from body.
Identify the tissue shown in the diagram and match with its characteristics and its location
Skeletal muscle tissue is closely attached to skeletal bones. In a typical muscle such as the biceps, striated (striped) skeletal muscle fibres are bundled together in a parallel fashion.
A particle of mass m oscillates along x-axis according to equation x= a sin ωt. The nature of the graph between momentum and displacement of the particle is
As v²/a²ω² + y²/a² = 1 This is the equation of an ellipse. Hence the graph is an ellipse. P versus x graph is similar to v versus x graph.
Select the correct option with respect to cockroaches
In cockroaches, males bear a pair of short thread‑like anal styles which are absent in females.
Select the alternative giving correct identification and function of the
organelle ‘A’ in the diagram.
In fig., (A) shows the cell organelle mitochondria The mitochondria are bounded by two membranes, i.e., outer membrane and inner membrane. Mitochondria are referred as “powerhouse” of the cell as they produce 95% of ATP. This energy is produced during the break down of food molecules which involve glycolysis, Oxidative decarboxylation and oxidative phosphorylation (krebs cycle and respiratory chain).
The length of the wire between two ends of a sonometer is 100 cm. What should be the positions of two bridges below the wire so that the three segments of the wire have their fundamental frequencies in the ratio of 1: 3 : 5 ?
From the formula, f = 1/x√T/m
⇒ f ∝ 1/l
∴ l₁ : l₂ : l₃ = 1/f₁ : 1/f₂ : 1/f₃
= f₂ f₃ : f₁ f₃: f₁ f₂
(Given, f₁ : f₂ : f₃ = 1 : 3 : 5)
=15: 5 : 3
Therefore the positions of two bridges below the wire are
15 x 100/ 15+ 5 +3 cm and 15 x 100 + 5 x 100/ 15 + 5 + 3cm
i.e., 1500/23 cm 2000/23 cm
Why is a capsule advantageous to a bacterium?
Capsule is a layer that lies outside the cell wall bacteria. The capsule can protect cells from engulfment by eukaryotic cells, such as macrophages. They also exclude bacterial viruses and most hydrophobic toxic materials such as detergents.
Two sources P and Q produce notes of frequency 660 HZ each. A listener moves from P to Q with a speed of 1 ms⁻¹ If the speed of sound is 330 m/s, then the number of beats heard by the listener per second will be
∆f/f = v/c
⇒ (Beats)/2/f = v/c
⇒ Beats = 2 fv/c = 4
Which of the following statements about enzymes is wrong?
Almost all enzymes are proteins. There are some nucleic acids that behave like enzymes. There are called ribozyme (also called RNA enzyme or catalytic RNA).
A charge ‘q’ is placed at the centre of the line joining two equal charges ‘Q’. The system of the three charges’ will be in equilibrium if‘ "q” is equal to
The system of three charges will be in equilibrium.
For this, force between charge at A and B + force between charge at point O and either at A or B is zero
i. e. , kQ²/(2r)² + kQq/(r)² = 0
By solving we get,
q =- Q/4
An electric dipole of dipole moment p is aligned parallel to a uniform electric field E. The energy required to rotate the dipole by 90⁰ is
When electric dipole is aligned parallel
θ = 0° and the dipole is rotated by 90° i.e.,
θ = 90°
Energy required to rotate the dipole
W = U_f - Uᵢ = (- pE cos 90°) −(-pE cos 0°)
= pE.
The figure shows a hypothetical tetrapeptide portion of a protein with parts labelled A-D. Which one of the following option is correct?
Glutamic acid and aspartic acid are acidic amino acids with two carboxylic groups and one amino group
A stage of mitosis is shown in the diagram. Which stage is it and what are its characteristics?
Metaphase chromosome is made up of two sister chromatids which are held together by the centromere. Chromosomes are moved to spindle equator and gets aligned along metaphase plate through spindle fibers to both poles.
A healthy person eats the following diet – 5 gm raw sugar, 4 gm albumin, 10 gm pure buffalo ghee adulterated with 2 gm vegetable ghee (hydrogenated vegetable oil) and 5 gm lignin. How many calories is he likely to get?
Physiological value of carbohydrates is 4.0 kcal/g, proteins 4.0 kcal/g and of fats is 9.0 kcal/g. Hence, 5 g raw sugar will yield 5 × 4.0 = 20.0 kcal
4 g albumin (protein) will yield 4 × 4.0
= 16.0 kcal 10 + 2 g of fat will yield 12 × 9.0 = 108.0 kcal Total yield = 144 kcal.
Which enzymes are likely to act on the baked potatoes eaten by a man, starting from the mouth and as it moves down the alimentary canal?
Chemical process of digestion started in the oral cavity by the hydrolytic action of the carbohydrate (potato contains starch) splitting enzyme, the salivary amylase. Carbohydrates in the chyme are hydrolysed by pancreatic amylase into disaccharides.
Which one of the following is one of the paths followed by air/O₂ during respiration in an adult male Periplaneta americana as it enters the animal body?
The number of spiracles in cockroach is 10‑pairs (2‑pairs in thoracic and 8‑pairs in abdominal region). The thoracic pairs of spiracles are present on pleuron between prothorax ‑ mesothorax and metathorax. Each spiracle opens into a chamber called atrium. After atrium the tracheal tube ramifies into fine branches of tracheae, and then tracheoles.
The figure shows a human blood cell. Identify it and give its characteristics.
Basophils secrete histamine, serotonin, heparin, etc., and are involved in inflammatory reactions.
Figure shows blood circulation in humans with labels A to D. Select the option which gives correct identification of label and functions of the part:
Artery is blood vessel which receives blood from heart, has elastic thick wall shows jerky movements due to pumping activity of heart. Vein is a blood vessel which carries blood towards the heart, has wider lumen with internal valves where blood flows smoothly and slowly. Blood capillary is a very fine blood vessel which has a single layered wall. Pulmonary veins are the only veins which carry oxygenated blood. (pO₂ = 95 mmHg, pCO₂ = 40 mmHg)
Two rods are joined end to end, as shown. Both have a cross-sectional area of 0.01 cm². Each is 1 meter long . One rod is of copper with a resistivity of 1.7 x 10⁻⁶ ohm -centimeter, the other is of iron with a resistivity of 10⁻⁵ ohm-centimeter.
How much voltage is required to produce a current Of 1 ampere in the rods?
Copper rod and iron rod are joined in series.
∴ R = R_Cu + R_Fe = (ρ₁ + ρ₂)l/A (∵ R = ρl/A)
From Ohm's law, V = RI
= (1.7 × 10⁻⁶ × 10⁻² + 10⁻⁵ × 10⁻²) ÷ 0.01 × 10⁻⁴ volt
= 0.117 volt (∵ I = 1 A)
Select the correct statement with respect to disorders of muscles in humans
Myasthenia gravis is a chronic autoimmune muscular disease. It causes breakdown of neuromuscular junction due to which the brain loses control over muscles. The difficulty symptoms may include drooping eyelids, difficulty in swallowing muscle fatigue, difficult breathing and inability to control facial expressions.
Select the option which shows correct matching of animal with excretory organs and excretory product.
Animal | Excretory organs | Excretory product |
|---|---|---|
(a) Housefly | Renal tubules | Uric acid |
(b) Labeo (Rohu) | Nephridial tubes | Ammonia |
(c) Salamander | Kidney | Urea |
(d) Peacock | Kidney | Urea |
Salamander (Amphibia; Caudata) excrete urea by help of kidneys.
A 12 cm wire is given a shape of a right angled triangle ABC having sides 3 cm, 4 cm and 5 cm as shown in the figure. The resistance between two ends (4B, BC, CA) of the respective sides are measured one by one by a multi meter. The resistances will be in the ratio of
Resistance is directly proportional to length.
1/R_AB = 1/3 + 1/4 + 5 = (4 + 5 )+ 3/(3)(4 + 5)
R_AB = 3×(4 + 5)/3 + (4 + 5) = 27/12
Similarly,
R_BC = 4×(3 + 5)/4 + (3 + 5) = 32/12
R_AC = 5×(3 + 4)/5 +( 3 + 4) = 35/12
∴ R_AB : R_BC : R_AC = 27 : 32 : 35
Ten identical cells connected in series are needed to heat a wire of length one meter and radius ‘r' by 10°C in time 't'. How many cells will be required to heat the wire of length
two meter of the same radius by the same temperature in time ‘t'?
Resistance is directly proportional to length of the wire. As length is doubled, so mass is doubled and resistance is doubled.
We have
(10E)²/R × t = mSΔT ,Now, (nE)²t/2R = (2m)SΔT
⇒ n²E²t / 2R = 2.10²E²t/R
⇒ n = 20
A long straight wire carries a certain current and produces a magnetic field of 2 x 10⁻⁴ weber/m² at a perpendicular distance of 5cm from the wire. An electron situated at 5 cm
from the wire moves with a velocity 10⁷ m/s towards the wire along perpendicular to it. The force experienced by the electron will be
(charge on electron =1.6 x 10⁻¹⁹ C)
Given:
Magnetic field, B = 2 × 10⁻⁴ weber/m²
Velocity of electron, v = 10⁷ m/s
Lorentz force,
F = qvB sin θ
= 1.6 × 10⁻¹⁹ × 10⁷ × 2 × 10⁻⁴ × sin 90°
= 3.2 × 10⁻¹⁶ N
A circular coil ABCD carrying a current i is placed in a uniform magnetic field. If the magnetic force on the segment AB is 𝐅⃗, the force on the remaining segment BCDA is
Here, 𝐅⃗_AB + 𝐅⃗_BCDA = 𝐎⃗
⇒ 𝐅⃗_BCDA = −𝐅⃗_AB = −𝐅⃗
(∵ F_AB = 𝐅⃗)
A bar magnet of magnetic moment M is placed at right angles to a magnetic induction B. If a force F is experienced by each pole of the magnet, the length of the magnet will
be
Torque FL=MB ⇒ L = MB/F
A current of 2.5 A flows through a coil of inductance 5 H. The magnetic flux linked with the coil is
Given: Current, I = 2.5 A
Inductance, L = 5 H
Magnetic flux, ϕ = ?
We know, ϕ = LI ⇒ 5 × 2.5 = 12.5 Wb
The primary of a transformer when connected to a dc battery of 10 volt draws a current of 1 mA. The number of turns of the primary and secondary windings are 50 and 100 respectively. The voltage in the secondary and the current drawn by the circuit in the secondary are respectively
A transformer is essentially an AC device. DC source so no mutual induction between the coils.
⇒ E₂ = 0 and I₂ = 0
An electromagnetic wave of frequency v = 3.0 MHz passes from vacuum into a dielectric medium with relative permittivity ε =4.0. Then
Given: Frequency, f = 2 MHz
Relative permittivity, ∈ᵣ = 4
From the formula,
velocity = c/√∈ᵣ = c/2 ⇒ λ' = λ/2
[since frequency remains unchanged]
Two plane mirrors are inclined at 70°. A ray incident on one mirror at angle 0 after reflection falls on second mirror and is reflected from there parallel to first mirror. The value of 0 is
From fig. 40°+ θ = 90° ∴ θ = 90°- 40°=50°
In Young’s double slit experiment the distance between the slits and the screen is doubled. The separation between the slits is reduced to half. As a result the fringe width
Fringe width, β = λD/d
From the question, D′ = 2D and d′ = d/2
∴ β′ = λD′/d′ = 4β
A parallel beam of light of wavelength . is incident normally on a narrow slit. A diffraction pattern is formed on a screen placed perpendicular to the direction of the incident beam.
At the second minimum of the diffraction pattern, the phase difference between the rays coming from the two edges of slit is
Conditions for diffraction minima are:
Path difference, Δx = nλ and Phase diff. δϕ = 2nπ
Path diff. = nλ = 2λ
Phase diff. = 2nπ = 4π (∵ n = 2)
The de-Broglie wavelength of neutron in thermal equilibrium at temperature T' is
From the formula, λ = h/√(2mkT)
= 6.63 × 10⁻³⁴ / √(2 × 1.67 × 10⁻²⁷ × 1.38 × 10⁻²³ × T) . m
(By placing the values of h, m and k)
= 30.8/√T Å
A source of light is placed at a distance of 50 cm from a photocell and the stopping potential is found to be V₀. If the distance between the light source and photocell is made 25 cm, the new stopping potential will be
Since stopping potential is independent of distance, the new stopping potential will remain unchanged i.e., new stopping potential = V₀
An electron in hydrogen atom makes a transition n₁ → n₂ where n₁ and n₂ are principal quantum numbers of the two states. Assuming Bohr's model to be valid the time period of the electron in the initial state is eight times that in the final state. The possible values of n₁ and n₂ are
∵ T ∝ n³
T₁/T₂ = 8T₂/T₂ = (n₁/n₂)³
Hence, n₁ = 2n₂
How does the binding energy per nucleon vary with the increase in the number of nucleons?
From the graph of BE/A versus mass number A it is clear that, BE/A first increases and then decreases with increase in mass number.
During muscle contraction in humans the
Increase in Ca⁺⁺ level into the sarcoplasm leads to the binding of calcium with a subunit of troponin on actin filaments and thereby remove the masking of active sites for myosin. Utilising the energy from ATP hydrolysis, the myosin head now binds to the exposed active sites on actin to form a cross bridge. This pulls the attached actin filaments towards the centre of ‘A’ band. The ‘Z’ lines attached to these actins are also pulled inwards thereby causing a shortening of the sarcomere, i.e., contraction. It is clear from the above steps, that during shortening of the muscle, i.e., contraction, the ‘I’ bands get reduced, whereas the ‘A’ bands retain the length.
α-particles, β-particles and γ-rays are all having same energy. Their penetrating power in a given medium in increasing order will be
Increasing order of penetrating power :
α< β< γ .
In an unbiased p-n junction, holes diffuse from the p-region to n-region because of
In p-region of p-n junction
holes concentration > electrons concentration and in n- region of p-n junction
electrons concentration > holes concentration.
One way in which the operation of a n-p-n transistor differs from that of a p-n-p
In p-n-p transistor holes are injected into the base while electrons are injected into the base of n-p-n transistor. Emitter-base junction is forward biased.
The output from a NAND gate is divided into two in parallel and fed to another NAND gate. The resulting gate is a
C′ = (A̅ · B̅)̅ ⇒ C = A̅̅ · B̅̅ = A · B
Hence, the resultant gate is AND gate.
The ratio of radii of gyration of a circular ring and a circular disc, of the same mass and radius, about an axis passing through their centres and perpendicular to their planes are
∵ I = MK² ∴ K = √(I/M)
I_ring = MR² and I_disc = 1/2 MR²
K₁/K₂ = √(I₁/I₂) = √MR²/(MR²/2) = √2 : 1
A charge g is located at the centre of a cube. The electric flux through any face is
Cube has 6 faces. Flux through any face is given by
ϕ = q/6ε₀ = q4π/6(4πε₀)
In an experiment it showed that 10 mL of 0.05 M solution of chloride required 10 mL of 0.1 M solution of AgNO₃. Which of the following will be the formula of the chloride (X stands for the symbol of the element other than
Millimoles of solution of chloride = 0.05 × 10 = 0.5 Millimoles of AgNO₃ solution = 10 × 0.1 = 1 So, the millimoles of AgNO₃ are double than the chloride solution. ∴ XCl₂ + 2AgNO₃ → 2AgCl + X(NO₃)₂
According to the law of photochemical equivalence, the energy absorbed (in ergs/mole) is given as (h = 6.62 × 10⁻²⁷ erg s, c = 3 × 10¹⁰ cm s⁻¹, Nₐ = 6.02 × 10²³ mol⁻¹)
E = hc/λ × N_A
= 6.62 × 10⁻²⁷ × 3 × 10¹⁰ × 6.02 × 10²³ / λ
= 1.19 × 10⁸ / λ ergs mol⁻¹
Which one of the following arrangements represents the correct order of least negative to most negative electron gain enthalpy for C, Ca, Al, F and O?
As the nuclear charge increases, the force of attraction between the nucleus and the incoming electron increases and hence the electron gain enthalpy becomes more negative, hence the correct order is
Ca < Al < C < O < F In which of the following pair both the species have sp³ hybridization?
Applying VSEPR theory, both NF₃ and H₂O are sp³ hybridized.
A sagittal section of human‑brain is shown here. Identify at least two labels from A‑D.
Cerebrum is the first and most developed part of forebrain. It makes 2/3rd part of total brain. Pons is a small spherical projection, which is situated below the midbrain and upper side of the medulla oblongata. It acts as a relay centre among different parts of brain. B and D are thalamus and spinal cord respectively.
The figure shows an axon terminal and synapse. Select the option giving correct identifications of labels A‑D
In the given figure, A, B, C and D are axon, neurotransmitters, receptors and synaptic vesicles respectively.
Which of the following represents the action of insulin?
Insulin is a peptide hormone, which plays a major role in the regulation of glucose homeostasis. Insulin acts mainly on hepatocytes and adipocytes (cells of adipose tissue), and enhances cellular glucose uptake and utilization. Insulin also stimulates conversion of glucose into glycogen (glycogenesis) in the target cells.
Norepinephrine: (1) Is released by sympathetic fibres
(2) Is released by parasympathetic fibres
(3) Increases the heart rate
(4) Decreases blood pressure
Which of the above said statements are correct?
Norepinephrine is released by sympathetic fibres i.e., rapidly secreted in response to stress of any kind and, during emergency situations. It increases the heart beat, the strength of heart contraction and the rate of respiration.
The figure shows a section of human ovary. Select the option which gives the correct identification of A and B with function/characteristic
The corpus luteum is a temporary endocrine structure in female mammals that is involved in the production of relatively high levels of progesterone. A marked in the figure shows primary follicle, a layer of granulosa cells, surrounds each primary oocyte. A large number of these follicles degenerate during the phase from birth to puberty.
Select the option which correctly matches the endocrine gland with its hormone and its function.
Endocrine gland | Hormone | Function |
|---|---|---|
(a) Ovary | FSH | Stimulates follicular development and the secretion of estrogens. |
(b) Placenta | Estrogen | Initiates secretion of the milk. |
(c) Corpus luteum | Estrogen | Essential for maintenance of endometrium. |
(d) Leydig | Androgen | Initiates the cells production of sperms. |
Leydig cells or interstitial cells, which are present in the intertubular spaces produce a group of hormones called androgens mainly testosterone. Androgens play a major stimulatory role in the process of spermato‑genesis (formation of spermatozoa).
One of the following is not a method of contraception – which one?
Oxytocin is birth hormone and acts on the smooth muscles of our body and stimulates their contraction. Vasopressin acts mainly at the kidney and stimulates resorption of water and electrolytes and reduces loss of water through urine. Hence, it is also called as anti‑diuretic hormone (ADH).
The foetal ejection reflex in humans triggers release of
Parturition is induced by a complex neuroendocrine mechanism. The signals for parturition originate from the fully developed foetus and the placenta which induce mild uterine contractions called foetal ejection reflex. This triggers release of oxytocin from the maternal pituitary.
‘Which one of the following statements is correct rega Sexually Transmitted Diseases (STD)?
STDs are more common in 15-24 years age group. Gonorrhoea, syphilis, genital herpes, chlamydiasis, genital warts, trichomoniasis, hepatitis-B and AIDS are some of the common STDs. Haemophilia is sex-linked recessive disease, which show its transmission from unaffected carrier female to some of male progeny. Sickle cell anaemia is an autoimmune linked recessive trait in which both the partners are carrier for the gene.
The stage transferred into the uterus after induced fertilization of ova in the laboratory is
In Intra‑Uterine Transfer (IUT) embryo with more than 8‑blastomeres stage (morula) is used for transfer into the uterus.
Which one is the incorrect statement with regards to the importance of pedigree analysis?
Pedigree is a chart showing the record of inheritance of certain genetic traits for two or more ancestral generations of an individual, abnormality or disease.
In our society women are blamed for producing female children. Choose the correct answer for the sex‑determination in humans
In case of humans, the sex determining mechanism is XY type. Out of 23 pairs of chromosomes, 22 pairs are exactly same in both males and females called autosomes. A pair of X‑chromosomes present in the female, whereas the presence of an X and Y chromosome are determinant of male characteristic. In case the ovum fertilises with a sperm carrying X‑chromosome the zygote develops into a female (XX) and the fertilisation of ovum with Y‑chromosome carrying sperm results into a male offspring.
Down’s syndrome in humans is due to
Down’s syndrome is the chromosomal disorders due to the presence of an additional copy of the chromosome number 21 (trisomy of 21). The affected individual is short statured with small round head, furrowed tongue and partially open mouth and mental development is retarded.
The figure gives an important concept in the genetic implication of DNA. Fill the blanks A, B and C.
In this question A is Francis Crick, B is translation and C is transcription. It is unidirectional flow of information from DNA to mRNA (transcription) and then decoding the information present in mRNA in the formation of polypeptide chain or protein (translation).
In an inducible operon, the genes are
Inducible operons are usually switched off. This is a type of operon which is switched on when a chemical called inducer is present. The inducer is almost always a substrate.
The finch species of Galapagos Islands are grouped according to their food sources. Which of the following is
Darwin observed an amazing diversity of creatures on Galapagos islands. He realised that there were many varieties of finches in the same island like seed‑eating, insect‑eating and cactus‑eating varieties.
Dinosaurs dominated the world in which of the following geological era?
Dinosaurs dominated the world in mesozoic era. In Triassic period, giant reptiles (dinosaurs) emerged. In Jurassic period, dinosaurs diversified and abundant (golden age of dinosaurs) and in cretaceous period, mass extinction of dinosaurs occurred.
Identify the site where Wuchereria bancrofti is normally found on human body
Wuchereria (W. bancrofti and W. malayi), filarial worms causing chronic inflammation of the organs in which they live for many years, usually the lymphatic vessels of the lower limbs and the disease caused by them known as elephantiasis or filariasis. The genital organs are mainly affected, resulting in gross deformities. The pathogens are transmitted to a healthy person through the bite by the female mosquito vectors.
Which one of the following is a hallucinogenic drug?
Hallucinogens are drugs that cause illusions and delusions (hallucinations) and change the feelings or perception. Examples are Bhang, Charas, Hashish, Marijuana (all cannabinoids) and LSD (Lysergic acid diethylamide). Opium and morphine are opiate narcotics (opioids) having analgesic (pain relieving effect) while caffeine is a stimulant that increases the activity of nervous system, and causes awakening.
Tissue culture technique can produce infinite number of new plants from a small parental tissue. The economic importance of the technique is in raising
The method of producing thousands of plants through tissue culture is called micro‑propagation. Each of these plants will be genetically identical to the original plant from which they were grown, i.e., they are somaclones. Many important food plants like tomato, banana, apple have been produced on commercial scale using this method.
Microbe used for biocontrol of pest butterfly caterpillars is
Microbial biocontrol agent that can be introduced in order to control butterfly caterpillars is the bacteria Bacillus thuringiensis (Bt). They are sprayed onto vulnerable plants, where they are eaten by the insect larvae. In the gut of the larvae, the toxin is released and the larvae get killed. The bacterial disease will kill the caterpillars, but leave other insects unharmed.
The age pyramid with broad base indicates
Age pyramid is a graphic representation of different age groups of population with pre‑reproductive groups at the base, reproductive ones in the middle and post‑reproductive groups at the top. In triangular age pyramid, the number of pre‑reproductive individuals is very large while reproductive are moderate and post‑reproductive are fewer.
When man eats fish which feeds on zooplankton which have eaten small plants, the producer in the chain is
Plants are producers which can prepare their food by the process of photosynthesis. Zooplanktons, fish and man are primary, secondary and tertiary carnivores respectively.
Which one of the following is not a parasitic adaptation?
In parasitism, one species (parasite) is benefited and the other (host) is harmed. Parasites have very high reproduction capacity. The life cycles of parasites are often complex, involving one or two intermediate hosts or vectors to facilitate parasitisation of its primary host.
Climate of the world is threatened by
The increase in the level of greenhouse gases (e.g., CO₂, CH₄, CFC, N₂O etc.) has led to the considerable heating of earth surface leading to global warming. The relative contributions of various greenhouse gases to global warming is: CO₂ (60%) > CH₄ (20%) > CFC (14%) > N₂O (6%)
Which one of the following is not correct as regards the harmful effects of particulate matter of the size 2.5 micro meters or less?
According to Central Pollution Control Board (CPCB) particulate size 2.5 micrometers or less in diameter are responsible for causing various breathing inflammations, damage to the lungs and premature deaths.
The outer orbitals of C in ethene molecule can be considered to be hybridized to give three equivalent sp² orbitals. The total number of sigma (σ) and pi (π) bonds in ethene molecule is
In which of the following ionisation processes the bond energy increases and the magnetic behaviour changes from paramagnetic to diamagnetic?
(a) N₂ ⟶ N₂⁺
B.O. 3, 2.5
Bond energy decreases.
Magnetic behaviour changes from diamagnetic to paramagnetic.
(b) O₂ ⟶ O₂⁺
B.O. 2 , 2.5
Bond energy increases.
Magnetic behaviour does not change.
(c) C₂ ⟶ C₂⁺
B.O. 2, 2.5
Bond energy decreases.
Magnetic behaviour changes from diamagnetic to paramagnetic.
(d) NO ⟶ NO⁺
B.O. 2 , 2.5
Bond energy increases.
Magnetic behaviour changes from paramagnetic to diamagnetic.
The pair of species that has the same bond order in the following is:
No. of electrons in CO = 6 + 8 = 14
No. of electrons in NO⁺ = 7 + 8 − 1 = 14
∴ CO and NO⁺ are isoelectronic species.
Isoelectronic species have identical bond order.
What is the density of N₂ gas at 227°C and 5.00 atm pressure? (R = 0.0821 atm K⁻¹ mol⁻¹)
Density = PM/RT = 5 × 28/0.0821 × 500 = 3.41 g/mL
When 5 litres of a gas mixture of methane and propane is perfectly combusted at 0°C and 1 atmosphere, 16 litre of oxygen at the same temperature and pressure is consumed. The amount of heat released from this combustion in kJ (ΔH_comb (CH₄) = 890 kJ mol⁻¹, ΔH_comb (C₃H₈) = 2220 kJ mol⁻¹) is
CH₄ (x ) + 2O₂ (2x)→ CO₂ + 2H₂O
C₃H₈ (5-x) + 5O₂ 5(5-x) → 3CO₂ + 4H₂O
2x + 5(5 − x) = 16
x = 3 L
∴ Heat released
= 3/22.4 × 890 + 2/22.4 × 2220 = 317
Three thermochemical equations are given below:
(i) C(graphite) + O₂(g) → CO₂(g); ΔᵣH° = x kJ mol⁻¹
(ii) C(graphite) + ½ O₂(g) → CO(g); ΔᵣH° = y kJ mol⁻¹
(iii)CO(g) + ½ O₂(g) → CO₂(g); ΔᵣH° = z kJ mol⁻¹
Based on the above equations, find out which of the relationship given below is correct?
Applying Hess's law, equation (i) can be obtained by adding equation (ii) and (iii).
∴ x = y + z
At 100°C the K_w of water is 55 times its value at 25°C. What will be the pH of neutral solution? (log 55 = 1.74)
K_w at 25°C = 1 × 10⁻¹⁴
At 25°C
K_w = [H⁺][OH⁻] = 10⁻¹⁴
At 100°C (given)
K_w = [H⁺][OH⁻] = 55 × 10⁻¹⁴
∵ For a neutral solution
[H⁺] = [OH⁻]
∴ [H⁺]² = 55 × 10⁻¹⁴
or [H⁺] = (55 × 10⁻¹⁴)¹ᐟ²
∵ pH = −log[H⁺]
On taking log on both side
−log[H⁺] = −log(55 × 10⁻¹⁴)¹ᐟ²
pH = ½(−log55 + 14log10)
pH = 6.13
Accumulation of lactic acid (HC₃H ₅o₃, a monobasic acid in tissues leads to pain and a feeling of fatigue. In a 0.10 M aqueous solution, lactic acid is 3.7% dissociated. The value of dissociation constant, Ka, for this acid will be:
α = √(Kₐ/C) = 0.037 = √(Kₐ/0.10)
Kₐ = (0.037)² × 0.10 = 1.37 × 10⁻⁴ = 1.4 × 10⁻⁴
The values of K_sp of CaCO₃ and CaC₂O₄ are 4.7 × 10⁻⁹ and 1.3 × 10⁻⁹ respectively at 25°C. If the mixture of these salts is washed with water, what is the concentration of Ca²⁺ ions in water?
CaCO₃ (x ) →Ca²⁺ + CO₃²⁻ (x )
CaC₂O₄ → Ca²⁺ (Y ) + C₂O₄²⁻ (Y )
∴ [Ca²⁺] = x + y
Now, K_sp(CaCO₃) = [Ca²⁺][CO₃²⁻]
or ,4.7 × 10⁻⁹ = (x + y)x
Similarly, K_sp(CaC₂O₄) = [Ca²⁺][C₂O₄²⁻]
or 1.3 × 10⁻⁹ = (x + y)y
On solving, we get
[Ca²⁺] = 7.746 × 10⁻⁵ M
The dissociation constant of a weak acid is 1 × 10⁻⁴. In order to prepare a buffer solution with a pH = 5, the [Salt]/[Acid] ratio should be
Given, K_a = 1 × 10⁻⁴
∴ pK_a = −log(1 × 10⁻⁴) = 4
Now from Henderson equation,
pH = pK_a + log([Salt]/[Acid])
Putting the values,
5 = 4 + log([Salt]/[Acid])
log([Salt]/[Acid]) = 5 − 4 = 1
Taking antilog,
[Salt]/[Acid] = 10 = 10 : 1
In Castner-Kellner cell for production of sodium hydroxide:
In Castner-Kellner cell, sodium amalgam is formed at mercury cathode.
Which statement is wrong?Feldspars are 3-dimensional alumino-silicates.
Arrange the following in increasing order of stability
Greater the number of e ̅ donating alkyl groups (+I effect), greater will be the stability of carbocations.
Homolytic fission of the following alkanes forms free radicals CH₃ – CH₃, CH₃ – CH₂ – CH₃, (CH₃)₂CH – CH₃, CH₃ – CH₂ – CH(CH₃)₂. Increasing order of stability of the radicals is
Stability depends on number of hyper conjugative structure.
What is the hybridisation state of benzyl carbonium
In the carbonium ion the carbon atom carrying the positive charge is sp² hybridized.
Nitrogen detection in an organic compound is carried out by Lassaigne’s test. The blue colour formed corresponds to which of the following formulae?
The prussian blue colour is of Fe₄[Fe(CN)₆]₃ ferrie ferrocyanide
Conformers are form of stereoisomers in which isomers can be interconverted by rotation about single bonds. I and Il are staggered and eclipsed conformers respectively.
In the following reaction :
Product ‘P’ will not give
Conformers are form of stereoisomers in which isomers can be interconverted by rotation about single bonds. I and Il are staggered and eclipsed conformers respectively.
Which of the following chemical system is non aromatic?
-
(A)
-
(B)
-
(C)
-
(D)
Huckel ruleis ot obeyed. Ithas only four electrons . further it does not have continous conjugation.
Which one of the following statements is not true?
Acid rain is the rain water containing sulphuric acid and nitric acid which are formed from the oxides of sulphur and nitrogen present in the air as pollutants. Rain water has a pH
below 5.6.
How many grams of cobalt metal will be deposited when a solution of cobalt (II) chloride is electrolyzed with a current of 10 amperes for 109 minutes (1 Faraday = 96,500 C; Atomic mass of Co = 59 u)
Applying,
w = Zit = Eit/96500
Equivalent weight of cobalt (II) = 59/2
I = 10 A
Time (t) = 109 min = 109 × 60 sec
Substituting these values we get,
w = (59 × 10 × 109 × 60) / (2 × 96500) = 20.0
Consider the half-cell reduction reaction: Mn²⁺ + 2e⁻ → Mn, E° = -1.18 V Mn²⁺ → Mn³⁺ + e⁻, E° = -1.51 V The E° for the reaction 3Mn²⁺ → Mn⁰ + 2Mn³⁺, and possibility of the forward reaction are, respectively
ΔE° = E°_red + E°_oxd = −1.81 − 1.51 = −2.69
Since ΔE° is negative,
∴ ΔG = −nF E°, ΔG will have positive value, so forward reaction is not possible.
A reaction is 50% completed in 2 hours and 75% completed in 4 hours. The order of
For a first order reaction,
t₇₅% = 2 × t₅₀%
For a reaction between A and B the order with respect to A is 2and the order with respect to Bis 3. The concentrations of both A and B are doubled, the rate will increase by a factor of :
Rate₁ = k[A]²[B]³
When concentrations of both A and B are doubled then,
Rate₂ = k[2A]²[2B]³ = 32k[A]²[B]³
∴ Rate will increase by a factor of 32.
The metal oxide which cannot be reduced to metal by
carbon is
Al₂O₃ cannot be reduced by carbon.
Identify the incorrect statement, regarding the molecule XeO₄:
Al₂O₃ cannot be reduced by carbon.
Sc (Z = 21) is a transition element but Zn (Z = 30) is not because
A transition element must have incomplete d-subshell Zinc have completely filled d subshell having 3d¹⁰ configuration. Hence do not show properties of transition elements to any appreciable extent except for their ability to form complexes.
Gadolinium belongs to 4f series. Its atomic number is 64. Which of the following is the correct electronic configuration of gadolinium?
Gd (64) = [Xe]4f⁷ 5d¹ 6s²
In a cymose inflorescence the main axis
In cymose inflorescence, the growth of the main axis is definite because the growing point of peduncle is used up in the formation of a flower. Further growth of flowering axis is continued by one or more lateral branches which also end in flower.
The correct IUPAC name for [CrF₂(en)₂]Cl is:
IUPAC name of [CrF₂(en)₂]Cl is
Difluorobis(ethylenediamine) chromium (III) chloride
In a particular isomer of [Co(NH₃)₄Cl₂] ⁰, the Cl–Co–Cl angle is 90°.
the isomer is known as .
Which is diamagnetic?
CN⁻ is a strong ligand and causes pairing of 3d electrons of Ni²⁺.
∴ It is diamagnetic.
The anion of acetylacetone (acac) forms Co(acac)₃ chelate with Co³⁺. The rings of the chelate are
CN⁻ is a strong ligand and causes pairing of 3d electrons of Ni²⁺.
∴ It is diamagnetic.
Which among the following is a paramagnetic complex?
(At. No. of Mo = 42, Pt = 78)
Co²⁺ ⇒ [Ar]3d⁷4s⁰, here, Br⁻ is a weak field ligand so will not cause pairing of d-electrons in Co²⁺.
∴ [CoBr₄]²⁻ will exhibit paramagnetic behaviour due to unpaired electrons.
Phenol is distilled with Zn dust followed by Friedel Crafts alkylation with propyl chloride in the presence of AlCl₃ to give a compound (B). (B) is oxidised in the presence of air to form the compound (C). The structural formula of (C) is
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(A)
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(B)
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(C)
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(D)
Some reactions of amines are given. Which one is correct ?
- (A) (CH₃)₂NH + NaNO₂ + HCl → (CH₃)₂N–N=O
- (B) CH₃NH₂ + C₆H₅SO₂Cl → CH₃NHSO₂C₆H₅
- (C) CH₃CH₂NH₂ + HNO₂ → CH₃CH₂OH + N₂
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(D)
Secondary amine react with nitrous acid to give N-Nitrosoamines.
On hydrolysis of a “compound”, two compounds are obtained. One of which on treatment with sodium nitrite and hydrochloric acid gives a product which does not respond to iodoform test. The second one reduces Tollen’s reagent and Fehling’s solution. The “compound” is
Hydrolysis of propyl isocyanide (CH₃CH₂CH₂NC) gives
CH₃CH₂CH₂NH₂ + HCOOH
On treatment with NaNO₂ and HCl, I gives CH₃CH₂CH₂OH which does not give iodoform test. II (HCOOH) reduces Tollens' reagent and Fehling's solution.
CH₃CH₂CH₂NC ( Propyl isocyanide ) + ---H₂O →
CH₃CH₂CH₂NH₂ (I )+ HCOOH (II )
In DNA, the linkages between different nitrogenous bases are :
The base pairs of the two strands of DNA are linked together through H-bonds.
Dettol is the mixture ofDettol is a mixture of chloroxylenol and terpineol.
Which condition is not satisfied by an ideal solution?
An ideal solution is that solution in which. each component obeys Raoult’s law under all conditions of temperatures and concentrations. For an ideal solution.
ΔH_mix = 0 and ΔV_mix = 0..
The outer electronic configuration of Gd (At. No. 64) is:
Gd [64] = [Xe]4f⁷5d¹6s²
Number of isomeric alcohols of molecular formula C₆H₁₄O which give positive iodoform test is
Gd [64] = [Xe]4f⁷5d¹6s²
Arrange the following in increasing order of stability
Greater the number of e ̅ donating alkyl groups (+I effect ),greater will be the stability of carbocations
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