question_answer

 The correct sequence of steps involved in the mechanism of Cannizzaro's reaction is

A) nucleophilic attack, transfer of \[{{\text{H}}^{\text{-}}}\] and transfer of \[{{\text{H}}^{+}}\]

B) transfer of \[{{\text{H}}^{-}}\], transfer of \[{{\text{H}}^{+}}\] and nucleophilic attack

C) transfer of \[{{\text{H}}^{+}}\] , nucleophilic attack and transfer of \[{{\text{H}}^{-}}\]

D) electrophilic attack by \[\text{O}{{\text{H}}^{-}}\], transfer of \[{{\text{H}}^{-}}\] and

Correct Answer: A

Solution :

The Cannizzaro reaction is as \[\text{HCHO + HCHO}\xrightarrow{\text{KOH(con}\text{.)}}\underset{\text{methyl alcohol}}{\mathop{\text{C}{{\text{H}}_{\text{3}}}\text{OH}}}\,\text{+}\underset{\text{acetic acid}}{\mathop{\text{HCOO}{{\text{k}}^{\text{+}}}}}\,\]The mechanism of Cannizzaro reaction is as Step I Attack of nucleophile \[\text{O}{{\text{H}}^{-}}\]to the carbonyl carbon Step II The transfer of hydride ion from anion (I) to second molecule of aldehyde and finally rapid transfer of proton takes place.