Chemistry - Salt Analysis Question with Solution | TestHub

Reaction: Sodium thiosulfate reacts with dilute acid to form sulfur dioxide gas, a yellow sulfur precipitate, sodium sulfate, and water.

Gas ($S{O}_2$): The central sulfur atom (S) keeps its bonds with oxygen to evolve as $S{O}_2$ gas, making (A) correct.

Precipitate (S^∗): The terminal sulfur atom (S^∗) breaks away to form the yellow precipitate of elemental sulfur (S^∗), making (B) correct.

Sodium Sulfate: The sulfate ion comes entirely from the input sulfuric acid ($H_{2}S{O}_4$), forming $N{a}_{2}S{O}_4$, making (C) correct.

Conclusion: The reaction is an intramolecular redox decomposition rather than a true disproportionation, so (D) is incorrect.