Question

Why we keep calcium chloride in dark coloured bottle?

Answer 1

because it is a very reactive with sunlight

Answer 2

Its stored in dark coloured bottlesbecause silver chloridereacts(decomposed) with sunlight. And dark coloured objects/bottlesobstruct light.to prevent it from reacting, its stored in dark colored bottles as ,by keeping in this sunlight won't be able to reach silver chloride