(i) A chemical reaction that proceeds by absorption of light is called a photo chemical reaction.
(ii) We stor silver chloride in dark coloured bottles in order to protect it from the effect of sunlight.
(iii) Sunlight decompose silver chloride and forms solver and chlorine.
`{:(2AgCl_((s))overset("Sunlight")to2Ag_((s))+Cl_(2)uarr),("Silver chloride" " ""Silver" " ""Chlorine"),(" "("white") " "("Gray")):}`
(iv) As dark coloured bottles obstruct light, silver chloride will get prevented from decomposition.
