MHTCET 13 Apr 2026 Shift 2 Paper

Concept:Colored compounds are shown by transition metal ions that have partially filled $d$-orbitals.Explanation:Check the $d$-electron configuration of each given ion.For $\mathrm{Sc}^{3+}$:$\mathrm{Sc}$ has configuration $[\mathrm{Ar}]\,3d^{1}4s^{2}$.After losing three electrons, $\mathrm{Sc}^{3+}$ becomes $[\mathrm{Ar}]\,3d^{0}$.It has no $d$-electrons, so it is colorless.For $\mathrm{Ti}^{4+}$:$\mathrm{Ti}$ has configuration $[\mathrm{Ar}]\,3d^{2}4s^{2}$.After losing four electrons, $\mathrm{Ti}^{4+}$ becomes $[\mathrm{Ar}]\,3d^{0}$.It also has no $d$-electrons, so it is colorless.For $\mathrm{Cu}^{+}$:$\mathrm{Cu}$ has configuration $[\mathrm{Ar}]\,3d^{10}4s^{1}$.After losing one electron, $\mathrm{Cu}^{+}$ becomes $[\mathrm{Ar}]\,3d^{10}$.It has completely filled $d$-orbitals, so it is generally colorless.For $\mathrm{V}^{3+}$:$\mathrm{V}$ has configuration $[\mathrm{Ar}]\,3d^{3}4s^{2}$.After losing three electrons, $\mathrm{V}^{3+}$ becomes $[\mathrm{Ar}]\,3d^{2}$.It has partially filled $d$-orbitals, which allow $d$–$d$ transitions and produce colored compounds.Answer:Therefore, the cation that forms colored compounds is $\mathrm{V}^{3+}$, which is option D.