Nesslefs reagent is used to detect

Question

Nesslefs reagent is used to detect (A) PO 43- (B) MNO 4- (C)  NH4+  (D)  CrO42-

Tardigrade Admin · Accepted Answer

Nessler's reagent is prepared by the reaction of mercuric chloride in the excess of KI.

H g C l_{2} + 2 K I ⟶ scarlet ppt. H g I_{2} + 2 K Cl

H g I_{2} + 2 K I ⟶ potassium tetraiodo mercurate(II) colourless complex K_{2} [H g I_{4}]

Alkaline solution of

K_{2} [H g I_{4}]

is called Nessler's reagent. It is used to test

N H_{3}

or

N H_{4}^{+}

ions which give brown precipitate or colouration with ammonia due to the formation of the iodide of Millon's base

H g_{2} N I \cdot H_{2} O

. It has the structure

Q. Nesslefs reagent is used to detect