Question

The correct option(s) to distinguish nitrate salts of ${Mn^{2+}}$ and ${Cu^{2+}}$ taken separately is (are)

• A. ${Mn^{2+}}$ shows the characteristic green colour in the flame test
• B. Only ${Cu^{2+}}$ shows the formation of precipitate by passing ${H_2S}$ in acidic medium
• C. Only ${Mn^{2+}}$ shows the formation of precipitate by passing ${H_2S}$ in faintly basic medium
• D. ${Cu^{2+} /Cu}$ has higher reduction potential than ${Mn^{2+} /Mn}$ (measured under similar conditions)

Answer 1

Answer: (D)

${Cu^{2+} /Cu}$ has higher reduction potential than ${Mn^{2+} /Mn}$ (measured under similar conditions)

Answer 2

(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) ${Cu^{+2} /Cu = +0.34 \, V \, (SRP)}$
${Mn^{+2} /Mn = - 1.18 \, V \, (SRP)}$