CBSE EXAMINATION PAPER-2024

The involvement of (n 1)d electrons in the behaviour of transition elements impart certain distinct characteristics to these elements. Thus, in addition to variable oxidation states, they exhibit paramagnetic behaviour, catalytic properties and tendency for the formation of coloured ions. The transition metals react with a number of non-metals like oxygen, nitrogen and halogens. KMnO 4 examples. and K 2 Cr 2 O 7 are common The two series of inner transition elements, lanthanoids and actinoids, constitute the f-block of the periodic table. In the lanthanoids, there is regular decrease in atomic size with increase in atomic number due to the imperfect shielding effect of 4f-orbital electrons which causes contraction. Answer the following questions :

The involvement of (n 1)d electrons in the behaviour of transition elements impart certain distinct characteristics to these elements. Thus, in addition to variable oxidation states, they exhibit paramagnetic behaviour, catalytic properties and tendency for the formation of coloured ions. The transition metals react with a number of non-metals like oxygen, nitrogen and halogens. KMnO 4 examples. and K 2 Cr 2 O 7 are common The two series of inner transition elements, lanthanoids and actinoids, constitute the f-block of the periodic table. In the lanthanoids, there is regular decrease in atomic size with increase in atomic number due to the imperfect shielding effect of 4f-orbital electrons which causes contraction. Answer the following questions :

The involvement of (n 1)d electrons in the behaviour of transition elements impart certain distinct characteristics to these elements. Thus, in addition to variable oxidation states, they exhibit paramagnetic behaviour, catalytic properties and tendency for the formation of coloured ions. The transition metals react with a number of non-metals like oxygen, nitrogen and halogens. KMnO 4 examples. and K 2 Cr 2 O 7 are common The two series of inner transition elements, lanthanoids and actinoids, constitute the f-block of the periodic table. In the lanthanoids, there is regular decrease in atomic size with increase in atomic number due to the imperfect shielding effect of 4f-orbital electrons which causes contraction. Answer the following questions :

Which of the following does not show variable oxidation states?

(CH₃)₂CH-O-CH₃ when treated with HI gives:

Which of the following compounds on treatment with benzene sulphonyl chloride forms an alkali-soluble precipitate?

The order of increasing basicities of CH₃NH₂ (I), (CH₃)₂NH (II), (CH₃)₃N (III) and C₆H₅NH₂ (IV) in aqueous media is:

The vitamin which plays an important role in coagulating blood is:

When a catalyst increases the rate of a chemical reaction, then the rate constant (k):

During the electrolysis of aqueous NaCl, the cathodic reaction is:

What type of deviation is shown by ethanol and acetone mixture? Give reason.What type of azeotropic mixture is formed by that deviation ?

A solution is prepared by dissolving 5 g of a non-volatile solute in 200 g of water. It has a vapour pressure of 31·84 mm Hg at 300 K. Calculate the molar mass of the solute.

(Vapour pressure of pure water at 300 K = 32 mm Hg)

A first-order reaction is 25 complete in 40 minutes. Calculate the value of rate constant. In what time will the reaction be 80 % complete ?

Given : log 2 = 0·30, log 3 = 0·48, log 4 = 0·60, log 5 = 0·69