question_answer

The conversion of benzaldehyde into benzyl alcohol takes place by :

A)  Fittig reaction

B)  Wurtz Fittig reaction

C)  Wurtz reaction

D)  Cannizaros reaction

Correct Answer: D

Solution :

Key Idea: Explain all term to find correct answer [a] Fittig reaction: Two molecules of aryl halide react to form diphenyl.                                         \[-2NaX\] [b] Wurtz Fitting reaction: One molecule of alkyl halide and one molecule of aryl halide combine in presence of sodium to form higher homologue of benzene.                                         \[+\,2NaX\] [c] Wurtz reaction: Two molecules of alkyl halide react together to form alkane having double number of carbon atoms as in alkyl halide. \[\underset{alkyl\text{ }halide}{\mathop{R-X}}\,\,\,+2Na+X-R\xrightarrow{{}}\underset{alkane}{\mathop{R-R}}\,\,\,+2NaX\] [d] Cannizaro reaction: Aldehydes which do not have \[\alpha \]-hydrogen atom undergo disproportion reaction (half of the molecule are oxidised and half are reduced.) \[\therefore \] Benzaldehyde is converted into benzyl alcohol by Cannizaro reaction.