Question

Sodium extract is heated with concentrated $HN{O}_3$ before testing for halogens because:

• A. ${Ag}_{2}S$ and $AgCN$ are soluble in acidic medium.
• B. silver halides are totally insoluble in nitric acid.
• C. $S^{2-}$ and $C{N}^{-}$, if present, are decomposed by conc. $HN{O}_3$ and hence do not interfere in the test.
• D. $Ag$ reacts faster with halides in acidic medium.

Answer 1

Answer: (C)

$S^{2-}$ and $C{N}^{-}$, if present, are decomposed by conc. $HN{O}_3$ and hence do not interfere in the test.

Sodium extract is heated with concentrated $HN{O}_3$ before testing for halogens because $S^{-2}$ and $C{N}^{-}$ ions if present are decomposed by conc. $HN{O}_3$ and hence do not interfere in the test.