Question

Which of the following relation(s) is/are correct regarding precipitation?
Here,
$K_{sp}$ is the solubility product and
$Q_{sp}$ ionic concentration product.

• A. When $\frac{K_{sp}}{Q_{sp}}<1$ , precipitation takes place.
• B. When $\frac{K_{sp}}{Q_{sp}}<1$ , precipitation does not takes place.
• C. When $\frac{K_{sp}}{Q_{sp}}>1$ , precipitation takes place.
• D. When $\frac{K_{sp}}{Q_{sp}}>1$ , precipitation does not takes place.

Answer 1

Answer: (A), (D)

The correct options are
A When $\frac{K_{sp}}{Q_{sp}}<1$ , precipitation takes place.
D When $\frac{K_{sp}}{Q_{sp}}>1$ , precipitation does not takes place.

When $K_{sp}<Q_{sp}$, the solution is supersaturated and ionic solid will start precipitating.
$\Rightarrow \frac{K_{sp}}{Q_{sp}}<1$, the solution is supersaturated and ionic solid will precipitate.
Similarly for, $\frac{K_{sp}}{Q_{sp}}>1$, it is a unsaturated solution, and more ions can dissolve. No precipitation takes place.
Option A and Option D are correct.