a
(a) \(\mathop {C{H_3} - C{H_2} - C \equiv }\limits_{{\text{But}} - {\text{1}} - {\text{yne}}} CH + {H_2}O \to \)  \(\left[ {C{H_3} - C{H_2} - \mathop {\mathop {C\,}\limits^{|\,\,\,\,} }\limits^{OH}  = C{H_2}} \right]\mathop {\xrightarrow{{{\text{keto - enol}}}}}\limits_{{\text{tautomerism}}} \)   \(\mathop {C{H_3} - C{H_2} - \mathop {\mathop C\limits^{||} }\limits^O  - C{H_3}}\limits_{{\text{Butan}} - {\text{2}} - {\text{one}}} \)