Question

Silver chloride dissolves in excess of ammonium hydroxide solution. The cation present in the resulting solution is:
A. ${[Ag{(N{H_3})_6}]^ + }$
B. ${[Ag{(N{H_3})_4}]^ + }$
C. $A{g^ + }$
D. ${[Ag{(N{H_3})_2}]^ + }$

Answer 1

Silver chloride belongs to a chemical compound with formula $AgCl$. Unlike chloride salts which are water soluble silver salts are not soluble in water. They dissolve in ammonium hydroxide by forming a soluble complex.

Complete step by step answer:
-An ammonium hydroxide solution is an aqueous solution of ammonia gas in water. This is represented by the formula $N{H_4}OH$. This consists of water (${H_2}O$) and ammonia ($N{H_3}$) rather than $N{H_4}^ +$ and $O{H^ - }$ ion.
-Silver chloride is an inorganic salt which is precipitated when the chloride ion reacts with silver nitrate. -The reaction is used in qualitative detection of chloride ions. The reaction can be shown as:
$AgN{O_3} + NaCl \to AgCl \downarrow + NaN{O_3}$
-The silver chloride is precipitated as white solid. The solid is then treated with aqueous ammonium hydroxide solution. In this reaction the solid gets soluble by formation of a complex. The reaction can be shown as:
$AgCl + 2N{H_4}OH \to [Ag{(N{H_3})_2}]Cl + {H_2}O$
Thus option D is the correct answer, i.e. ${[Ag{(N{H_3})_2}]^ + }$ will be the cation present in the solution.

Additional information: In general the halides are detected using $AgN{O_3}$ solution. The $AgX$ precipitate formed in this reaction shows different colors for different halides. $AgBr$ is pale yellow in color and $AgI$ is yellow precipitate. The anions to be detected in qualitative analysis are fused with sodium to produce the sodium salts like $NaCl$, $NaBr$ and $NaI$. The test is known as sodium fusion test or Lassaigne's test.

Note: The silver compound formed in the reaction is an example of coordination compound. The IUPAC name of the compound is Diammine silver (I) chloride.