The metallic ions that have almost same spin only magnetic moment are :

(i) $$\mathrm{Co}^{2+}$$

(ii) $$\mathrm{Mn}^{2+}$$

(iii) $$\mathrm{Cr}^{2+}$$

(iv) $$\mathrm{Cr}^{3+}$$

The correct order of increasing melting point is

Consider the following statements in respect of lanthanides, which of the statements are incorrect?

(i) $$\mathrm{La}(\mathrm{OH})_3$$ is least basic among the hydroxides of lanthanides

(ii) The lanthanide ions $$\mathrm{Yb}^{2+}, \mathrm{Lu}^{3+}$$ and $$\mathrm{Ce}^{4+}$$ are diamagnetic in nature.

(iii) $$\mathrm{Ce}^{4+}$$ can act as an oxidising agent

(iv) $$\operatorname{Ln}$$ (III) compounds are generally colourless

(v) Ionic radii of $$\mathrm{Ce}^{3+}$$ is greater than $$\mathrm{Yb}^{3+}$$

Arrange the following ions in the increasing order of their $$\Delta H_{(\text {hydration})}$$ values.

$$\mathrm{Cr}^{2+}, \mathrm{Co}^{2+}, \mathrm{Mn}^{2+}, \mathrm{Ni}^{2+}$$