question_answer

Acid catalysed hydration of alkenes except ethene leads to the formation of

A)  mixture of secondary and tertiary alcohols

B)  mixture of primary and secondary alcohols

C)  secondary or tertiary alcohol

D)  primary alcohol

Correct Answer: C

Solution :

\[C{{H}_{2}}=C{{H}_{2}}\xrightarrow{{{H}_{2}}O/{{H}^{+}}}\underset{{{1}^{o}}alcohol}{\mathop{C{{H}_{3}}C{{H}_{2}}OH}}\,\] \[C{{H}_{3}}-CH=C{{H}_{2}}\xrightarrow{{{H}_{2}}O/{{H}^{+}}}C{{H}_{3}}\underset{\begin{smallmatrix}  | \\  OH \end{smallmatrix}}{\mathop{C}}\,HC{{H}_{3}}\] \[{{2}^{o}}\]alcohol through\[{{2}^{o}}\]carbocation\[(C{{H}_{3}}\overset{\oplus }{\mathop{C}}\,HC{{H}_{3}})\] \[C{{H}_{3}}-\underset{\begin{smallmatrix}  | \\  C{{H}_{3}} \end{smallmatrix}}{\mathop{C}}\,=C{{H}_{2}}\xrightarrow{{{H}_{2}}O/{{H}^{+}}}{{(C{{H}_{3}})}_{3}}COH\] \[{{3}^{o}}\]alcohol through\[{{3}^{o}}\]carbocation\[[{{(C{{H}_{3}})}_{3}}\overset{\oplus }{\mathop{C}}\,]\] \[C{{H}_{3}}-\overset{\begin{smallmatrix}  C{{H}_{3}} \\  | \end{smallmatrix}}{\mathop{C}}\,H-CH=C{{H}_{2}}\xrightarrow{{{H}_{2}}O/{{H}^{+}}}\] \[C{{H}_{3}}\overset{\begin{smallmatrix}  C{{H}_{3}} \\  | \end{smallmatrix}}{\mathop{C}}\,H-CH-C{{H}_{3}}\xrightarrow{rearrangement}C{{H}_{3}}-\overset{\begin{smallmatrix}  C{{H}_{3}} \\  | \end{smallmatrix}}{\mathop{C}}\,-C{{H}_{2}}C{{H}_{3}}\]