CH3CHO and C6H5CH2CHO can be distinguished chemically by .(a) Benedict’s test (b) Iodoform test(c) Tollen’s reagent test (d) Fehling’s solution test

The compounds CH3CHO (Acetaldehyde) and C6H5CH2CHO (Benzaldehyde) can be distinguished chemically by the Iodoform test (b).

Here's the step by step process:

1. Iodoform Test: This test is based on the property of methyl ketones (and aldehydes) to be oxidized by iodine in the presence of a base, forming iodoform (CHI3), which is a yellow precipitate. Acetaldehyde (CH3CHO) will give a positive iodoform test, while Benzaldehyde (C6H5CH2CHO) will not, because it does not have a methyl group directly attached to the carbonyl carbon.

The other tests mentioned (Benedict’s test, Tollen’s reagent test, Fehling’s solution test) are all tests for reducing sugars or aldehydes in general, and both Acetaldehyde and Benzaldehyde would give positive results, so they cannot be used to distinguish between these two compounds.