An aqueous solution of a lead(II) salt is divided into two test tubes. Addition of potassium iodide to the first test tube produces a yellow precipitate 'X' which dissolves in boiling water and recrystallizes on cooling. Addition of potassium chromate to the second test tube produces a yellow precipitate 'Y' which is insoluble in acetic acid. The chemical identities of precipitates X and Y respectively are:

Step-by-step solution

The reaction of Pb²⁺ with KI yields a yellow precipitate of lead iodide ( PbI₂ ). A unique characteristic of PbI₂ is that it dissolves in boiling water to give a colorless solution and recrystallizes as golden spangles upon cooling. The reaction of Pb²⁺ with K₂CrO₄ yields a yellow precipitate of lead chromate ( PbCrO₄ ), which is insoluble in acetic acid but soluble in sodium hydroxide. Thus, X is PbI₂ and Y is PbCrO₄ . Answer: X = PbI₂ , Y = PbCrO₄