CBSE EXAMINATION PAPER-2024

20.         The nature of bonding, structure of the coordination compound can be explained to some extent by valence bond theory. The central metal atom/ion makes available a number of vacant orbitals equal to its coordination number. The appropriate atomic orbitals (s, p and d) of the metal hybridise to give a set of equivalent orbitals of definite geometry such as square planar, tetrahedral, octahedral and so on. A strong covalent bond is formed only when the orbitals overlap to the maximum extent. The d-orbitals involved in the hybridisation may be either inner d-orbitals i.e. (n—l) d or outer d-orbitals i.e. nd. The complexes formed are called inner orbital complex (low spin complex) and outer orbital complex (high spin complex) respectively. Further, the complexes can be paramagnetic or diamagnetic in nature. The drawbacks of this theory are that this involves number of assumptions and also does not explain the colour of the complex.

Answer the following questions :

Which of the following acids represents Vitamin C?

Rosenmund reduction is used for the preparation of Aldehydes. The catalyst used in this reaction is.

Which alkyl halide from the given options will undergo SN1 reaction faster?

From the elements of 3d series given below, which element shows the maximum number of oxidation states?

Identify the tertiary amine from the following:

Nucleophilic addition of Grignard reagent to ketones followed by hydrolysis with dilute acids forms

In a given graph of zero order reaction, the slope and intercept are:

Assertion (A): p-nitrophenol is less acidic than phenol. Reason

(R): Nitro group is electron withdrawing and helps in the stabilization of p-nitrophenoxide ion.

Assertion (A): Benzoic acid does not undergo Friedel–Crafts reaction. Reason

(R): Carboxyl group is deactivating and the catalyst aluminium chloride gets bonded to the carboxyl group.

Assertion (A): Fructose is a reducing sugar.

Reason (R): Fructose does not reduce Fehling solution and Tollen's reagent.

The general electronic configuration of d-block elements is :

Consider the following reaction :