Question

why do we store silver chloride in dark coloured bottles

Answer 1

Dark coloured bottles interrupt the path of light such that light cannot reach silver chloride in the bottles and its decomposition is prevented. It is known that silver chloride decomposes to silver and chlorine in the presence of light.

Answer 2

so that sunlight dosen't reaches it .Because as soon as it comes in contact of sunlight it decomposes into silver and chlorine.