Question

Select the one which describe the best among all the given options.

To determine whether a water solution of $N{a}_2{S}_2{O}_3$ at room temperature is supersaturated, one can:

• A. heat the solution to its boiling point
• B. add water to the solution
• C. add a crystal of $N{a}_2{S}_2{O}_3$ to the solution
• D. acidify the solution
• E. cool the solution to its freezing point

Answer 1

The correct option is C add a crystal of $N{a}_2{S}_2{O}_3$ to the solution

To determine whether a water solution of $N{a}_2{S}_2{O}_3$ at room temperature is supersaturated, one can add a crystal of $N{a}_2{S}_2{O}_3$ to the solution.
The amount of solute dissolved in a supersaturated solution is more than that permitted by solubility.
Hence, when a crystal of $N{a}_2{S}_2{O}_3$ is added to a supersaturated solution, some $N{a}_2{S}_2{O}_3$ will immediately come out of the solution. This will not happen if a crystal is added to saturated or unsaturated solution.