A chloride salt solution acidified with dil. HNO3 gives a curdy white precipitate, [A], on addition of AgNO3. [A] on tre

Question

A chloride salt solution acidified with dil. HNO3 gives a curdy white precipitate, [A], on addition of AgNO3. [A] on treatment with NH4OH gives a clear solution, B. The correct products are:

Accepted Answer

Given: A chloride salt solution acidified with dil. HNO $_3$ gives a curdy white precipitate [A] with AgNO $_3$ , and [A] dissolves in NH $_4$ OH to give clear solution B.

Find: The identities of [A] and B.

Chloride ion reacts with silver nitrate to form silver chloride, which appears as a curdy white precipitate.

\text{Cl}^- + \text{AgNO}_3 \rightarrow \text{AgCl} \downarrow

Therefore, [A] = AgCl.

Silver chloride dissolves in ammonia due to formation of a soluble diammine silver complex.

\text{AgCl} + 2\text{NH}_3 \rightarrow [\text{Ag}(\text{NH}_3)_2]\text{Cl}

Therefore, B = [Ag(NH $_3$ ) $_2$ ]Cl.

The correct option is C.

Given: The precipitate is curdy white and becomes a clear solution on treatment with NH $_4$ OH.

Find: Which products match these observations.

A curdy white precipitate with AgNO $_3$ is the characteristic test for chloride ion, so the precipitate must be AgCl.

Ammonia acts as a complexing ligand for Ag $(^+)$ and converts insoluble AgCl into a soluble complex species, giving a clear solution. Hence the dissolved product is [Ag(NH $_3$ ) $_2$ ]Cl.

Thus the pair is AgCl and [Ag(NH $_3$ ) $_2$ ]Cl, so the correct option is C.

Reaction scheme showing chloride ion with silver nitrate forming curdy white precipitate AgCl labeled A, followed by AgCl with NH4OH forming soluble complex [Ag(NH3)2]Cl labeled B.

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