Question

The solubility of a salt at different temperatures is tabulated below:
$$\begin{array}{cccccc}\text{Temperature (degree celsius)}& \text{20}& \text{30}& \text{40}& \text{50}& \text{60}\\ \text{Solubility (g per 100 ml)}& \text{34.2}& \text{37.2}& \text{40.1}& \text{42.6}& \text{45.8}\end{array}$$

Deepti takes 50 ml of water and adds 20 g of salt to it. The temperature of the solution is ${20}^{\circ }$C. Choose the correct statement.

• A. The solution formed will be unsaturated.
• B. The salt will dissolve completely and form a supersaturated solution.
• C. The salt will dissolve completely to form a saturated solution with no residual.
• D. The salt will dissolve to form a saturated solution and some undissolved salt will be left at the bottom.

Answer 1

The correct option is D

The salt will dissolve to form a saturated solution and some undissolved salt will be left at the bottom.

The solubility of the salt at ${20}^{\circ }$C= 34.2 g per 100 ml

Amount of solvent present = 50 ml

Amount of solute required to make a saturated solution = $\frac{34.2g}{100ml}\times 50ml=17.1g$

Since a greater amount of salt is present, 17.1 g of salt will dissolve completely to form a saturated solution. Rest of the salt will be in the form of crystals and will settle down at the bottom.