The transition metal having the highest $3^{rd}$ ionisation enthalpy is:

Among the following series of transition metal ions,the one where all metal ions have $3d^2$ electronic configuration is

Iron $(Fe)$ is classified as:

Which of the following salts is colourless?

Match the metal ions given in Column-$I$ with the spin magnetic moments of the ions given in Column-$II$ and assign the correct code.

Column-$I$	Column-$II$
$(a) \ Co^{3+}$	$(i) \ \sqrt{8} \ B.M.$
$(b) \ Cr^{3+}$	$(ii) \ \sqrt{35} \ B.M.$
$(c) \ Fe^{3+}$	$(iii) \ \sqrt{3} \ B.M.$
$(d) \ Ni^{2+}$	$(iv) \ \sqrt{24} \ B.M.$
	$(v) \ \sqrt{15} \ B.M.$

$(a) \quad (b) \quad (c) \quad (d)$

The magnetic moment of $M^{x+}$ (atomic number $= 25$) is $\sqrt{15} \ BM$. The number of unpaired electrons and the value of $x$,respectively,are