$2\mathrm{g}$ of silver, chloride is taken in a china dish and the china dish is placed in sunlight for some time. What will be your observation in this case? Write the chemical reaction involved in the form of a balanced chemical equation. Identify the type of chemical reaction.

Silver chloride is a light-sensitive chemical because it reacts when exposed to light. ${\mathrm{Ag}}^{+}$ ions (silver cations) and ${\mathrm{Cl}}^{-}$ ions (chloride anions) are closely packed to form silver chloride. As a result, it has a chemical name $\mathrm{AgCl}$.

The light-sensitive silver chloride complex breaks down into silver and chlorine when exposed to sunshine. Two electrons are released when chloride ions oxidise to generate the bimolecular chlorine gas Cl₂, which is then picked up by two silver cations, which then reduce to form elemental silver.
Silver metal is grey, while silver chloride is a crystalline solid that is white in colour. The change in colour from the white of silver chloride to the grey of metallic silver will therefore be the observation in this case. It can be said as a photochemical decomposition reaction. The resulting chemical reaction can be expressed as follows:
$2{\mathrm{AgCl}}_{\left(\mathrm{s}\right)}\stackrel{\mathrm{sunlight}}{\to }2{\mathrm{Ag}}_{\left(\mathrm{s}\right)}+{\mathrm{Cl}}_{2\left(\mathrm{g}\right)}$

Hence, the correct answer is option B.