• # question_answer 66) Nessler's reagent is used for the test of A) $S{{O}_{4}}$                                 B) $C{{O}_{3}}$C) $N{{H}^{+}}_{4}$                      D) $C{{O}_{2}}$

Nessler's reagent ${{K}_{2}}Hg{{I}_{4}}$is used to detect the presence of$N{{H}_{4}}^{+}$.When the given salt is warmed with  small amount of NaOH; a gas is  given out which gives a brown precipitate. Hence, the correct option is [c].