JEE Main 2026 — Practical Chemistry Question with Solution

The group reagent $H_{2}S$ in the presence of $N{H}_{4}OH$ is used for the precipitation of Group IV cations in qualitative analysis.

Among the given ions, $M{n}^{2+}$ belongs to Group IV and is precipitated as $MnS$.

$P{b}^{2+}$ and $C{u}^{2+}$ belong to Group II and are precipitated by $H_{2}S$ in an acidic medium.

$F{e}^{3+}$ belongs to Group III and is precipitated as $Fe(OH{)}_3$ by $N{H}_{4}OH$ in the presence of $N{H}_{4}Cl$.

The metal corresponding to the precipitated ion is Manganese ($Mn$).

The electronic configuration of $Mn$ is $[Ar]3d^{5}4s^2$. By losing all its valence electrons, it can exhibit a maximum oxidation state of $+7$ (for example, in $KMn{O}_4$).

Answer: $+7$