Question

The correct option(s) to distinguish nitrate salts of Mn²⁺ and Cu²⁺ taken separately is (are) :-
(A) Mn²⁺ shows the characteristic green colour in the flame test
(B) Only Cu²⁺ shows the formation of precipitate by passing H₂S in acidic medium
(C) Only Mn2+ shows the formation of precipitate by passing H₂S in faintly basic medium
(D) Cu²⁺/Cu has higher reduction potential than Mn²⁺/Mn (measured under similar conditions)

Answer 1

Answer: (B,D)

Solution:

(A) Cu⁺² and Mn⁺² both gives green colour in flame test and cannot distinguished.
(B) Cu⁺² belongs to group-II of cationic radical will gives ppt. of CuS in acidic medium.
(C) Cu⁺² and Mn⁺² both form ppt. in basic medium.
(D) Cu⁺²/Cu = +0.34 V (SRP)
Mn⁺²/Mn = – 1.18 V (SRP)