Question

Which of the following is most soluble in water?

• A. $\mathrm{AgI}$
• B. $\mathrm{AgF}$
• C. $\mathrm{AgCl}$
• D. $\mathrm{AgBr}$

Answer 1

The correct option is B

$\mathrm{AgF}$

Explanation for correct option:

B. $\mathrm{AgF}$

Solubility of silver halides in water:

• On moving down the group in halogens, the ionic size increases but the hydration energy decreases.
• When a compound is dissolved, the solubility depends upon the amount of hydration energy released.
• If the hydration energy is equal to or more than the lattice energy, then the salt is water-soluble.
• As the hydration energy decreases due to the increases in ionic size. Thus, the solubility also decreases on moving down the group.
• Therefore, the most soluble halide in water is Silver fluoride $\left(\mathrm{AgF}\right)$.

The trend for solubility of halides in water is as follows:

$\mathrm{AgF}>\mathrm{AgCl}>\mathrm{AgBr}>\mathrm{AgI}$

Hence, the correct option is B i.e. $\mathrm{AgF}$