Question

Nessler's reagent is an aqueous solution which contains

• A. Sodium chloride
• B. Mercuric chloride
• C. Potassium Hydroxide
• D. alkalic $K_{2}Hg{I}_4$

Answer 1

• ​Nessler's reagent an alkaline aqueous solution of potassium tetraiodomercurate (II)
• It contains aqueous solution of potassium iodide, mercuric chloride, and potassium hydroxide.
• Its chemical formula is $K_{2}Hg{I}_4$.
• It is used to detect the presence of ammonia.
• It turns into pale brown colour in presence of ammonia.

Hence, option (D) is correct.