In neutral or faintly alkaline medium, ${\mathrm{KMnO}}_4$ being a powerful oxidant can oxidise, thiosulphate almost quantitatively, to sulphate. In this reaction overall change in oxidation state of manganese will be

Which one amongst the following are good oxidising agents?

(a) ${\mathrm{Sm}}^{2+}$

(b) ${\mathrm{Ce}}^{2+}$

(c) ${\mathrm{Ce}}^{4+}$

(d) ${\mathrm{Tb}}^{4+}$

Choose the most appropriate answer from the options given below :

How many of the following metal ions have similar value of spin only magnetic moment in gaseous state? ________

(Given: Atomic number$:\mathrm{V},23; \mathrm{Cr},24; \mathrm{Fe},26; \mathrm{Ni},28)$

${\mathrm{V}}^{3+}, {\mathrm{Cr}}^{3+}, {\mathrm{Fe}}^{2+}, {\mathrm{Ni}}^{3+}$

The set of correct statements is:

(i) Manganese exhibits $+7$ oxidation state in its oxide.

(ii) Ruthenium and Osmium exhibit $+8$ oxidation in their oxides.

(iii) $\mathrm{Sc}$ shows $+4$ oxidation state which is oxidizing in nature.

(iv) $\mathrm{Cr}$ shows oxidising nature in $+6$ oxidation state.