Why do we store silver chloride in dark coloured bottles?

Explanation

Silver chloride `(AgCl)` is sensitive to sunlight. When exposed to it, the salt decomposes into silver (grey in colour) and chlorine. In order to check the decomposition, silver chloride (silver bromide also) is kept in dark coloured bottles so that sun light may not fall on it.
`AgCl(s) overset("Sunlight")to Ag(s) + 1//2 Cl_(2)(g)`