Question

Which among the following statements is/are true?

Exposure of silver chloride to sunlight for a long duration turns grey due to

(i) the formation of silver by decomposition of silver chloride.

(ii) sublimation of silver chloride

(iii) release of chlorine gas from silver chloride

(iv) oxidation of silver chloride

• A. (i) only
• B. (i) and (iii)
• C. (ii) and (iii)
• D. (iv) only

Answer 1

The correct option is A

(i) only

Explanation:

(i)

• When silver chloride $\left(\mathrm{AgCl}\right)$ is exposed to light, it decomposes to form silver $\left(\mathrm{Ag}\right)$ metal and chlorine gas $\left({\mathrm{Cl}}_2\right)$.
• The chemical equation of the reaction is:

$2\mathrm{AgCl}\left(\mathrm{s}\right)\stackrel{\mathrm{light}}{\to }2\mathrm{Ag}\left(\mathrm{s}\right)+{\mathrm{Cl}}_2\left(\mathrm{g}\right)$

• Due to the formation of silver metal, the color of silver chloride changes from white to grey.

(ii) Silver chloride does not sublime but rather decomposes into silver metal and chlorine gas.

(iii) Chlorine gas is produced in the decomposition of silver chloride but it is greenish-yellow, not gray in color.

(iv) Silver chloride is reduced to silver and thus, there is no oxidation of $\mathrm{AgCl}$ occurs.

Hence, option (A) is correct. (i) statement is true.