An ammoniacal metal salt solution gives a brilliant red precipitate on addition of dimethylglyoxime. The metal ion is :

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

The reaction of zinc with excess of aqueous alkali, evolves hydrogen gas and gives :

In following pairs, the one in which both transition metal ions are colourless is :