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. (b) Wurtz Fittig reaction: One molecule of alkyl halide and one molecule of aryl halide combine in presence of sodium to form higher homolog of benzene. (c) Wurtz reaction: Two molecules of alkyl halide react together to form alkane having double number of carbon atoms as in alkyl halide.                 \[\underset{\text{alkyl}\,\text{halide}}{\mathop{R-X}}\,+2Na+X-R\xrightarrow{{}}\underset{\text{alkane}}{\mathop{R-R}}\,+2NaX\] (d) Cannizaro reaction: Aldehydes which do not have a-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.