An organic compound contains C,H,N,S and Cl. For the detection of chlorine the sodium extract of the compound is first heated with a fewdropsof concentrated HNO_(5) and then AgNO_(3) is added to get a white ppt of AgCl. The digestion with HNO_(3) beforethe addition of AgNO_(3) is

An organic compound contains C,H,N,S and Cl. For the detection of chlo

1.	An organic compound contains C,H,N,S and Cl. For the detection of chlorine the sodium extract of the compound is first heated with a fewdropsof concentrated HNO_(5) and then AgNO_(3) is added to get a white ppt of AgCl. The digestion with HNO_(3) beforethe addition of AgNO_(3) is
Answer» To prevent the FORMATION of `AgNO_(3)` is To create a common ion effect To convert `CN^(-)` and `S^(2-)` to volatile `HCN`and `H_(2)S`, or else they will interfere with the test forming `AGCN` or `Ag_(2)S`. To prevent the hydrolysis of `NaCN` and `Na_(2)S` Solution :`Na+C+Noverset(Delta)rarrNaCN, 2Na+S overset(Delta)rarr Na_(2)S` Both `NaCN` and `Na_(2)S` will react with `AgNO_(3)` to form `AgCN` (white ppt.) and `Ag_(2)S` (black pt.) They must be removed before performing `AgNO_(3)` test for halogens Thus, on adding `HNO_(3),NaCN` and `Na_(2)S` `NaCN + HNO_(3) rarr NaNO_(3) + HCN UARR` `Na_(2)S + 2HNO_(3) rarr 2 NaNO_(3) + H_(2)S uarr` Hence, `CN^(-)` and `S^(2-)`are removed as HCN and `H_(2)S` by adding `HNO_(3)`. Hence, CHOICE (c) is correct while (a), (b) and (c)incorrect.