question_answer

Directions : In the following question more than one of the answers given may be correct. Select the correct answer and mark it according to the code:

The Cannizaro reaction is given by: (1)\[HCHO\]                                       (2) \[{{C}_{6}}{{H}_{5}}CHO\] (3) \[{{(C{{H}_{3}})}_{3}}CCHO\]               (4)\[C{{H}_{3}}CHO\]

A)  1, 2 and 3 are correct

B)  1 and 2 are correct

C)   2 and 4 are correct

D)  1 and 3 are correct

Correct Answer: A

Solution :

                 Aldehyde containing no a-hydrogen atom on reaction with 50%\[NaOH\]or KOH undergo disproportionation to give an alcohol and Na or K salt of an acid. This is called Cannizaro  reaction. \[2HCHO+KOH\xrightarrow{\Delta }C{{H}_{3}}OH+HCOOK\] \[2C{{H}_{3}}\underset{\begin{smallmatrix}  | \\  C{{H}_{3}} \end{smallmatrix}}{\overset{\begin{smallmatrix}  C{{H}_{3}} \\  | \end{smallmatrix}}{\mathop{C}}}\,-CHO\xrightarrow{\Delta }C{{H}_{3}}\underset{\begin{smallmatrix}  | \\  C{{H}_{3}} \end{smallmatrix}}{\overset{\begin{smallmatrix}  C{{H}_{3}} \\  | \end{smallmatrix}}{\mathop{C}}}\,-C{{H}_{2}}OH+C{{H}_{3}}\underset{\begin{smallmatrix}  | \\  C{{H}_{3}} \end{smallmatrix}}{\overset{\begin{smallmatrix}  C{{H}_{3}} \\  | \end{smallmatrix}}{\mathop{C}}}\,-COOK\]