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 $Cu^{2 +}$ ion to form white coloured complex
• D. $NH_{3}$ reacts with $Cu^{2 +}$ ion to give green precipitate

Answer 1

Answer: (A)

Ammonia is used in detection of $Cu^{2 +}$ ion because aqueous solution of $NH_{3}$ reacts with $Cu^{2 +}$ ion to form deep blue coloured complex.

$Cu _{( aq )}^{2+}+4 NH _{3( aq )} \rightarrow\left[ Cu \left( NH _{3}\right)_{4}\right]_{( aq )}^{2+}$ Deep blue