Question

Benzaldehyde and propanaldehyde can be chemically distinguished by

Answer 1

Benzaldehyde being an aldehyde reduces Tollen's reagent to give a red-brown precipitate of Cu2O, but acetophenone being a ketone does not. Acetophenone being a methyl ketone undergoes oxidation by sodium hypoiodite (NaOI) to give a yellow ppt. of iodoform. But benzaldehyde does not respond to this test.

Answer 2

Since Mg2+ cation has a higher charge and smaller radius than Na+ cation, it has a higher charge density and greater polarising power. This results in the Cl electron cloud in MgCl2 being distorted to a greater extent