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Give reason for the following: (i). Si...

Give reason for the following:
(i). Silver ornament gets tarnished when exposed to atmosphere for a long time.
(ii) Silver nitrate solution is kept in dark coloured bottles.
(iii). Why does `AgNO_3` produce a black stain on the skin.

Text Solution

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(i). Ag reacts slowly with trace of `H_2S` in air forming a black layer of `Ag_2S` on surface.
`2Ag+H_2Stounderset(Black)(Ag_2S)+H_2`
(ii). `AgNO_3` is photosensitive, It decomposes in presence of light. To prevent its decomposition, it is kept in coloured bottles as these do not permit light to pass through.
(iii). In the presence of organic matter and light `AgNO_3`, Decomposes to give a black stain of metallic silver.
`2AgNO_3to2Agdarr+2NO_2+O_2`
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