Question

What change in colour is observed when white silver chloride is left exposed in sunlight? State the type of chemical reaction and also write its chemical equation.

Answer 1

Hint: The energy packets (photons) from the sunlight break down and interact with the AgCl molecule. The light energy or the photons from the sunlight decompose the molecule.

Complete step by step answer:
When silver chloride is left exposed in the sunlight, the photons from the sunlight decompose the silver nitrate into native silver and chlorine gas. These types of reactions are known as photolytic decomposition reactions. In these reactions, the reactant molecule gets decomposed into two resultant molecules or products. The source of energy is light energy in the form of photons (energy packets). The chemical reaction involved in the process is given below:
\[2AgC{l_{(s)}} \to 2A{g_{\left( s \right)}} + C{l_{2\left( g \right)}}\]
Silver chloride (AgCl) is white in colour and elemental silver (Ag) is grey in colour.
Hence, the colour change observed when white silver chloride is left exposed in sunlight is from white to grey and the type of chemical reaction is photolytic decomposition reaction or photolysis.

Additional information:
Some uses of elemental silver are:
Silver is a precious metal. Hence, it is used for making jewelleries.
Silver is also used in photography to treat the film with a silver solution.
Silver is very extensively used in electronic gadgets.
Silver is non-toxic to humans and is used as a medicine.

Note: Remember that the source of energy in these types of reactions is light energy from the sun. Photons break down and decompose the parent molecule.