What are interstitial compounds? Explain them with reference to transition metals and mention their two important properties.

Represent by ionic equation, the oxidising action of ${\mathrm{MnO}}_4^{-}$ both in acidic and alkaline media. Write the balanced chemical equation of ${\mathrm{SO}}_2$ and ${\mathrm{MnO}}_4^{-}$ in acidic medium.

Decide giving reasons which one of the following exhibits the property indicated:

(i) ${\mathrm{Sc}}^{3+}$ and ${\mathrm{Cr}}^{3+}$ Exhibits paramagnetism.

(ii) $\mathrm{V} \mathrm{or} \mathrm{Mn}$  Exhibit number of oxidation states (at. no. $\mathrm{Sc}=21, \mathrm{V}=23,\mathrm{Cr}=24,\mathrm{Mn}=25$)

Complete the reactions:

${\mathrm{Na}}_2{\mathrm{Cr}}_2{\mathrm{O}}_7+\mathrm{KCl}⟶$

Complete the reactions:

Complete the reactions:

Giving reasons indicate which one of the following would be coloured?

${\mathrm{Cu}}^{+},{\mathrm{Vo}}^{2+},{\mathrm{Sc}}^{3+},{\mathrm{Ni}}^{2+}$

(atomic number : $\mathrm{Cu}=29, \mathrm{V}=23,\mathrm{Sc}=21,\mathrm{Ni}=28$)