Chapter 12, Problem 12.85AP

a.

Interpretation Introduction

Interpretation:

When the benzaldehyde undergoes oxidation in the presence of ${\text{K}}_{\text{2}}{\text{Cr}}_{\text{2}}{\text{O}}_{\text{7}}$, the product formed has to be determined.

Concept introduction:

Oxidation of aldehydes using ${\text{K}}_{\text{2}}{\text{Cr}}_{\text{2}}{\text{O}}_{\text{7}}$:

If an aldehyde undergoes oxidation, as it contain one hydrogen atom bonded to a carbonyl carbon, it gives carboxylic acid.

b.

Interpretation Introduction

Interpretation:

The product formed when the benzaldehyde reacts with Tollens reagent has to be determined.

Concept introduction:

Oxidation of aldehyde using Tollens reagent:

Aldehydes can be oxidized selectively in the presence of other functional groups using silver(I) oxide (${\text{Ag}}_{\text{2}}\text{O}$) in aqueous ammonium hydroxide (${\text{NH}}_{\text{4}}\text{OH}$). This combination is called as Tollens reagent. Only aldehydes do react with Tollens reagent; while other functional groups like ketone and alcohol are inert. Oxidation with Tollens reagent provides a distinct color change because the ${\text{Ag}}^{+}$ reagent is converted to silver metal ($\text{Ag}$), which precipitates out of the reaction mixture as a silver mirror.