Question

A china dish weighs 25 g when empty. When a saturated solution of potassium chloride is poured into it at 40${}^o$C, the weight of the dish is 63 g. When the solution is totally evaporated, the chine dish along with the crystals weighs 40 g. Find the solubility of potassium chloride at 40${}^0$C.

• A. 35
• B. 65.2
• C. 39.5
• D. 7.5

Answer 1

The correct option is C 39.5

A china dish weighs 25 g when empty. When a saturated solution of potassium chloride is poured into it at ${40}^{o}C$, the weight of the dish is 63 g.

Hence, the weight of $KCl$ solution is $63-25=38$ g.

When the solution is totally evaporated, the chine dish along with the crystals weighs 40 g.

The weight of solid $KCl$ is $40-25=15$ g.

The solubility of potassium chloride at ${40}^{o}C=$ $\frac{15}{38}\times 100=39.5$ g $KCl$ / 100 g solution.

Hence, the option ($C$) is the correct answer.