Pure carbon is not easily available

The enthalpy of formation of CO₂ is more than that of Al₂O₃

It is an expensive proposition

The enthalpy of formation of Al₂O₃ is very high

It has two 2e−3c bonds

It is an electrom deficient molecule

All the B−H bond lengths are equal

It has four 2e−2c bonds

N₂ does not react with metallic lithium at room temperature to form Li₃N

Hydrolysis of Mg₃N₂ gives NH₃

NH₃ is a stronger Lewis base than PH₃

Maximum covalency of nitrogen is 3

CO

CO₂

SO₂

SO₃

Al₄C₃

Be₂C

Mg₂C₃

Both (2) and (3)