question_answer

Give reasons for the following: (i) tert-butyl benzene does not give benzoic acid on treatment with acidic \[KMn{{O}_{4}}\] (ii)\[C{{H}_{2}}=\overline{C}H\] is more basic than \[HC\equiv \overline{C}\]

Answer:

                (i) Tertiary butyl benzene \[{{C}_{6}}{{H}_{5}}C{{(C{{H}_{3}})}_{3}}\]  does not give benzoic acid on reacting with acidified \[KMn{{O}_{4}}\]  because it does not contain a hydrogen atom attached directly to the carbon atom. (ii) We know that \[HC\equiv CH\]  is a stronger acid (\[sp\]-hybridised carbon atoms) than\[{{H}_{2}}C=C{{H}_{2}}\] (\[s{{p}^{2}}\]-hybridised carbon atoms). The conjugate base \[(HC\equiv \overset{\_}{\mathop{C}}\,)\] is, therefore, weaker than the conjugate base\[({{H}_{2}}C=\overset{\_}{\mathop{C}}\,H).\]