Question

silver nitrate solution is kept in a laboratory in coloured reagent bottles why

Answer 1

Silver nitrate solution is kept in a laboratory in colored reagent bottles because if it is kept in colorless bottle than it would react with sunlight  which will cause oxidation and as a result it would decomposed to silver oxide.

Answer 2

"Silver nitrate" is a very reactive silver compound which can readily react with sunlight and atmospheric oxygen to form silver oxide. With sunlight it decomposes to silver and silver oxide that can easily precipitate out.  

Therefore to prevent the photo-dissociation of molecule, silver nitrate solution is kept in a laboratory in coloured reagent bottles so that no direct contact will occur with sunlight that will prevent the dissociation of molecules.