Complete the reactions:

${\mathrm{MnO}}_4^{-}+{\mathrm{C}}_2{\mathrm{O}}_4^{2-}+{\mathrm{H}}^{+}⟶$

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

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

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

Account for the following statements:

$\mathrm{Co}\left(\mathrm{II}\right)$ is stable in aqueous solution but in the presence of strong ligands and air it can get oxidised to $\mathrm{Co} \left(\mathrm{III}\right)$ (at. no. $\mathrm{Co}=27$)

Account for the following statements:

of the ${\mathrm{d}}^4$ species, $\mathrm{Cr} \left(\mathrm{II}\right)$ is strongly reducing but $\mathrm{Mn} \left(\mathrm{III}\right)$ is strongly oxidising (at. no.  $\mathrm{Cr}=24,\mathrm{Mn}=25,\mathrm{Co}=27$)

Decide giving reason which one of the following pairs has the property indicated.

$\mathrm{Fe}$ or $\mathrm{Cu}$ has higher melting point.

Decide giving reason which one of the following pairs has the property indicated.

${\mathrm{Co}}^{2+}$ or ${\mathrm{Ni}}^{2+}$ has lower magnetic moment

Assign reasons for the following :

${\mathrm{Ce}}^{3+}$ can easily be oxidised to ${\mathrm{Ce}}^{4+}$