MCQs – Chemical Reactions and Equations class 10 science

Review

Question:  What happens when silver bromide is exposed to sunlight?

Correct Answer

When silver bromide is put under sunlight, it gives silver (Ag) metal and Bromine (Br₂) gas.

2AgBr(s) + Sunlight → 2Ag(s) + Br₂

Here, since silver bromide decomposes after getting energy from sunlight, hence this reaction is called Thermal Decomposition, Decomposition Reaction or Endothermic Reaction.

In this reaction silver bromide turns into grey due to sunlight. This happens because of formation of silver metal. Because of turning of grey colour of silver bromide, this reaction is used in black and white photography.

There is another similar reaction, which is also used in black and white photography.

On exposure of silver chloride under sunlight, it gives silver (Ag) metal and Chlorine (Cl₂) gas.

2AgCl(s) + Sunlight → 2Ag(s) + Cl₂(g)

In this reaction aslo silver chloride turns into grey due to sunlight. This happens because of formation of silver metal.