Question

Which of the following can be decomposed by the action of light?

• A. NaCl
• B. KCl
• C. AgCl
• D. CuCl

Answer 1

Answer: (C)

AgCl

$AgCl$ can be decomposed by the action of light because light catalysed the reaction as $AgCl$ is quite stable in the dark.
AgCl consists of crystals of tightly packed ions of silver and chlorine, denoted $A{g}^{+}$ and $C{l}^{-}$. When a film containing $A{g}^{+}$ and $C{l}^{-}$ is exposed to light energy, the chlorine ion's extra electron is ejected and then captured by a silver ion.