Question

You are given three unlabeled test tubes. One test tube contains a solution of ${Na}_2{SO}_4$, the second contains a solution of ${NaHSO}_3$ and the other contains $NaHS{O}_4$.
Describe how you could identify the solutions.

• A. Color change
• B. Odour test
• C. pH measurement
• D. Precipitate formation

Answer 1

The correct option is C pH measurement

The three test-tubes can be identified by measuring the $pH$ of the solution as the $pH$ is different for three compounds.

The increasing order of the pH is ${NaHSO}_4<{NaHSO}_3<{Na}_2{SO}_4$.