${\mathrm{Cr}}_2{\mathrm{O}}_7^{2-}$ ions are in equilibrium with ${\mathrm{CrO}}_4^{2-}$ ions at $\mathrm{pH}=4.$ The yellow chromate solution is obtained when

Which of the following statement(s) is correct about the action of heat on ${\mathrm{KMnO}}_4$?

[Note # Wrong answer option is given in the book]

Assign reason for the following:

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

Assign reason for the following:

$\mathrm{Lu}(\mathrm{OH}{)}_3$ is a weaker base than $\mathrm{La}(\mathrm{OH}{)}_3.$

Explain:

why are ${\mathrm{Sm}}^{2+}, {\mathrm{Eu}}^{2+}$ and ${\mathrm{Yb}}^{2+}$ good reducing agent?