Describe and activity to show decomposition reaction in which light is used to decompose a reactant. Write chemical equation of the reaction and state its one use. (2012)
Take about 2 g silver chloride in a china dish. It is first white in colour. Now place this china dish in sunlight for some time. After some time it is observed that white silver chloride turns grey. This is due to the decomposition of silver chloride into silver and chlorine by light.
2AgCl 2Ag (s) + Cl2 (g)
Silver bromide also decomposed to silver and bromine by light.
2AgBr 2Ag (s) + Br2 (g)
Use: The reaction is used in black and white photography.
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Which among the following statement(s) is(are) true? Exposure of silver chloride to sunlight for a long duration turns grey due to:
(i) The formation of silver by decomposition of silver chloride
(ii) Sublimation of silver chloride
(iii) Decomposition of chlorine gas from silver chloride
(iv) Oxidation of silver chlorideEvergreen Science
Which of the following are exothermic processes?
(i) Reaction of water with quicklime
(ii) Dilution of an acid
(iii) Evaporation of water
(iv) Sublimation of camphor (crystals)Evergreen Science