Question

Ion present in the Nessler's reagent is:

• A. $H{g}^{+}$
• B. $H{g}^{+2}$
• C. ${\left[Hg{I}_4\right]}^{-2}$
• D. ${\left[Hg\right(N{H}_3{)}_4]}^{+2}$

Answer 1

Answer: (C)

${\left[Hg{I}_4\right]}^{-2}$

$[Hg{I}_4{]}^{2-}$ is known as Messler Reagent.

It is used as a confirmatory test of $N{H}_3$

$N{H}_3+[Hg{I}_4{]}^{2-}$ gives Iodine of Millon's base of Reddish- Brown precipitation as shown in above image.