Chemistry - Salt Analysis Question with Solution | TestHub

(P) S₂O₃²⁻ (thiosulfate ion): Thiosulfate reacts with dilute acids like H₂SO₄ to produce sulfur dioxide gas and a precipitate of elemental sulfur, thus giving off fumes/gas.

(Q) BO₃³⁻ (borate ion): Borates are commonly identified by the green flame test, where a volatile borate ester (like trimethyl borate) is formed and burned, producing a characteristic green flame.

(R) PO₄³⁻ (phosphate ion): Phosphates are identified by the canary yellow precipitate test using ammonium molybdate solution, which forms ammonium phosphomolybdate.

(S) SO₃²⁻ (sulfite ion): Sulfites react with dilute acids such as H₂SO₄ to liberate sulfur dioxide gas, which has a pungent smell and gives off fumes/gas.