An article to be electroplated by silver is taken as cathode during electrolysis. The electrolyte to be taken during this process would be

Only small amounts of ‘Ag’ is required to electroplate the articles, a layer of silver is required;So Silver ion must not be freely available.Only small amounts of Silver ion must be obtained from the electrolyte;Silver ion if present as a complex cannot be ionized easily. Very little amount of it will be available due to  decomposition of complex ion;So a complex salt, KAgCN2 of silver is selected as the electrolyte;