Question

The following ion is coloured in aqueous solution :

• A. Zn${}^{2+}$
• B. Cd${}^{2+}$
• C. Co${}^{2+}$
• D. all the above

Answer 1

The correct option is C Co${}^{2+}$

In a normal metal atom, the only possible energy jumps are too great for visible light to be affected, and so the solutions appear colourless.

For $Z{n}^{2+}$ and $C{d}^{2+}$, there are no unpaired electrons which will be excited which results in color solution of the transition metals. Hence, they are colourless.