What is the state of hybridisation of carbon in (a)`CO_(3)^(2-)`, (b) diamond and ( c) graphite?

Explanation

To determine the state of hybridization of carbon in the given compounds (a) CO₃²⁻, (b) diamond, and (c) graphite, we will analyze each case step by step.

### Step 1: Hybridization in CO₃²⁻ (Carbonate Ion)

1. **Identify the structure**: The carbonate ion (CO₃²⁻) has one carbon atom bonded to three oxygen atoms.
2. **Count the bond pairs**: In CO₃²⁻, the carbon forms three sigma bonds with the oxygen atoms and has one lone pair.
3. **Determine hybridization**: The presence of three bond pairs indicates that the hybridization is sp². This is because sp² hybridization involves one s orbital and two p orbitals, resulting in three hybrid orbitals arranged in a trigonal planar geometry.

...