question_answer

Benzyl alcohol is obtained from Benzaldehyde by

A)  Fittig reaction

B)  reduction with \[LiAl{{H}_{4}}\]

C)  Cannizaros reaction

D)  Both (a) and (b)

Correct Answer: D

Solution :

                 Key Idea Fittig reaction In the Fittig reaction two molecules of haloarene combines with metallic sodium in the presence of anhydrous ether to give diphenyl.                 Cannizaros reaction Aldehydes which do not contain any a-hydrogen atom undergo self-oxidation and reduction reaction on treatment with cone. solution of caustic alkali. In this reaction one molecule is oxidised to acid while another molecule is reduced to alcohol.                 Benzyl alcohol is obtained from benzaldehyde by the reduction with \[LiAl{{H}_{4}}\] and Cannizaros reaction. \[{{C}_{6}}{{H}_{5}}CHO+2[H]\xrightarrow{LiAl{{H}_{4}}}\underset{benzal\,\,alcohol}{\mathop{{{C}_{6}}{{H}_{ & 5}}C{{H}_{2}}OH}}\,\] \[\underset{\begin{smallmatrix}  benzaldehyde \\  \left( No\text{ }\alpha -H\text{ }atom \right) \end{smallmatrix}}{\mathop{2{{C}_{6}}{{H}_{5}}CHO}}\,\xrightarrow[Cannizaros\text{ }reaction~]{50%\,\,NaOH}\]\[\underset{benzyl\text{ }alcohol}{\mathop{{{C}_{6}}{{H}_{5}}\,.\,C{{H}_{2}}OH}}\,\]                                                 \[+{{C}_{6}}{{H}_{5}}.COONa\]