Chapter Practice

Why fluorine stabilises the low oxidation states of transition metals?

Explain why ${\mathrm{Cr}}_2{{\mathrm{O}}_7}^{2-}$ ion is a powerful oxidant in acidic medium but weak oxidant in basic medium?

In the titration of ${\mathrm{Fe}}^{2+}$ ion in ${\mathrm{KMnO}}_4$ in acidic medium, dilute ${\mathrm{H}}_2{\mathrm{SO}}_4$ is used but not the dilute $\mathrm{HCl}$. Why?

Arrange the following oxides of Mn in the order of their decreasing acidic nature.

$\mathrm{MnO}, {\mathrm{Mn}}_2{\mathrm{O}}_3, {\mathrm{Mn}}_3{\mathrm{O}}_4, {\mathrm{MnO}}_2, {\mathrm{Mn}}_2{\mathrm{O}}_7$.

How ${\mathrm{KMnO}}_4$ can be obtained from ${\mathrm{MnO}}_2, \mathrm{KOH}$ and ${\mathrm{KNO}}_3$?

${\mathrm{K}}_2{\mathrm{PtCl}}_6$ is a well-known compound whereas the corresponding $\mathrm{Ni}$ compound is not known. State the reason for it.

Describe the factors on which the stability of an oxidation state of lanthanoid elements depends.

What is the effect of lanthanoid contraction on the chemistry of the lanthanoids?