Question

The correct option(s) to distinguish nitrate salts of $M{n}^{2+}$ and $C{u}^{2+}$ taken separately is (are)

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

Answer 1

Answer: (B), (D)

The correct options are
B Only $C{u}^{2+}$ shows the formation of precipitate by passing $H_{2}S$ in acidic medium
D $C{u}^{2+}/Cu$ has higher reduction potential than $M{n}^{2+}/Mn$ (measured under similar conditions)

$C{u}^{2+}$ shows the characteristic green colour in the flame test.
$K_{sp}$ of CuS < $K_{sp}$ of MnS. Hence, only $M{n}^{2+}$ shows formation of precipitate by passing $H_{2}S$ in faintly basic medium.
$E_{C{u}^{2+}/Cu}^{\circ }>E_{M{n}^{2+}Mn}^{\circ }$