Question

In Nessler's reagent for the detection of ammonia, the active species is ______.

1. $H_{2}C{l}_2$

2. $Hg{I}_4^{2-}$

Answer 1

Nessler's reagent is used for the detection of ammonia or ammonium ion. When Nessler's reagent is added to the ammonia solution, brown colour precipitate is obtained.

The active species in this is $Hg{I}_4^{2-}$.

Hence, the correct option is (2).