Question

Ammonia is used in detection of $Cu^{2+}$ ion because

• A. aqueous solution of $NH_3$ reacts with $Cu^{2+}$ ion to form deep blue coloured complex
• B. $NH_3$ reacts with $Cu^{2+}$ ion to give blue precipitate of $CuO$
• C. aqueous solution of $NH_3$ reacts with $Cu^{2+}$ to form white coloured complex
• D. $NH_3$ reacts with $Cu^{2+}$ ion to give green precipitate

Answer 1

Answer: (A)

$Cu^{2+}_{(aq)} +4NH_{3(aq)} \rightarrow \underset{\text{Deep blue}}{[Cu(NH_3)_4]^{2+}_{(aq)}}$