Question

Sparingly soluble salt is
(A) $KCl$
(B) $NaCl$
(C) $N{{H}_{4}}Cl$
(D) $BaS{{O}_{4}}$

Answer 1

Hint: When a salt is stirred in water and only a small amount of it gets dissolved but a large amount of it remains undissolved, then the salt is known as sparingly soluble salt. The solution gets saturated with only a small amount of salt. Sparingly means as little as possible. These salts have very low solubility.

Complete Step by Step Answer:
A salt is a substance that contains cations and anions. When a salt is dissolved in water, it dissociates into cations and anions. A sparingly soluble salt has little tendency to dissociate into cations and anions when dissolved in water. Among the given salts, $BaS{{O}_{4}}$is the sparingly soluble salt. The reason for this is that barium ($Ba$) belongs to the second group of the periodic table. The solubility of the sulphates of the second group decreases with an increase in atomic size. Hence, the hydration energy decreases and it becomes less soluble.
Hence, the correct answer is Option: (D)$BaS{{O}_{4}}$.

Additional Information: The solubility product of a sparingly soluble salt forming a saturated solution in water is calculated as the product of the concentrations of the ions raised to a power equal to the number of the ions occurring in the equation representing the dissociation of the electrolyte. The solubility product is denoted by ${{K}_{sp}}$.

Note: The solubility of salts of the second group decreases down the group. Hence, the solubility of sulphates decreases from $Be$to $Ba$. Other examples of sparingly soluble salts are silver chloride ($AgCl$) and calcium carbonate ($CaC{{O}_{3}}$ ) etc.