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

Hint: 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.