Question

HF in the vapour state is associated with covalent molecules while aqueous HF is ionic. Explain.

Answer 1

1.HF( Hydrogen fluoride) is a covalent molecule as the bond is formed between two non metals H and F.

2.HF in vapour state do not contain any ions though there is large electronegativity difference and hence it is covalent in nature.

3.HF in aqueous state, due to the polarisation by water, there is a charge separation in HF and forms $H^{+}and{F}^{-}$and hence the bond is ionic in nature.