Question
Which amongst the following is the strongest acid?
A.
$$CHB{r_3}$$
B.
$$CH{l_3}$$
C.
$$CH{\left( {CN} \right)_3}$$
D.
$$CHC{l_3}$$
Answer :
$$CH{\left( {CN} \right)_3}$$
Solution :
Due to the resonance stabilisation of the conjugate base, $$CH{\left( {CN} \right)_3}\,$$ is the strongest acid amongst the given compounds.
The conjugate bases of $$CHB{r_3}\,{\text{and}}\,CH{l_3}$$ are stabilised by inductive effect of halogens. This is why, they are less stable. Also, the conjugate base of $$CHC{l_3}$$ involves back-bonding between $$2p\,{\text{and}}\,3p$$ orbitals.
Due to the resonance stabilisation of the conjugate base, $$CH{\left( {CN} \right)_3}\,$$ is the strongest acid amongst the given compounds.
The conjugate bases of $$CHB{r_3}\,{\text{and}}\,CH{l_3}$$ are stabilised by inductive effect of halogens. This is why, they are less stable. Also, the conjugate base of $$CHC{l_3}$$ involves back-bonding between $$2p\,{\text{and}}\,3p$$ orbitals.