Question

Explain hybridisation in $HCN$ and ${H{N_3}}$.

Answer 1

Hint:To solve this question firstly we shall understand the term hybridisation and the concept behind it. We will study all the related information which will further lead us in learning about the hybridisation in HCN and ${H{N_3}}$. And hence, following these steps, we will be approaching our answer.

Complete step-by-step answer:
> Hybridisation is the mixing of two or more pure atomic orbital of an atom with almost same energy to give the same number of identical and degenerate new types of orbital is known as hybridisation. During hybridisation the atomic orbital with different characteristics is mixed with each other.
> For determining the hybridisation take a valence electron of the central atom, add monovalent surrounding atom and divide the whole by two.
It is 0.5 (V+ M + C+ A)
So,
V= No. Of Valence electron in central atom
M= no. Of monovalent atom
C= no. Of cation
A= total ion charge
> We have to assign the central atom. In this case it is C
- Now we have to connect the atom and form a bond. We have now C—N (triple bond) and C—H
- HCN has a triple bond and therefore it is a linear molecule. Linear molecule has a 180-degree bond angle.
- So, in $HCN$ hybridisation of C is sp.
- In ${H{N_3}}$ also known hydrazoic acid hybridisation is sp kind with ${H{N_3}}$ is near linearity (while the (N-N-N) bond angle is 171 degree.

Note: Hybridisation is used to determine the shape of the molecule. The amount of P orbital and S orbital which is decided mainly by orbital hybridisation can be used to predict molecular properties like acidity or basicity.