Which of the following $3\mathrm{d}-\mathrm{metal}$ ion will give the lowest enthalpy of hydration $\left({\mathrm{\Delta }}_{\mathrm{hyd}}\mathrm{H}\right)$ when dissolved in water?

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.