Which of the following are correct? (i) $\mathrm{V}^{2+}$ liberates hydrogen from a dilute acid (ii) The…
Which of the following are correct?
(i) $\mathrm{V}^{2+}$ liberates hydrogen from a dilute acid
(ii) The earlier members of lanthanide series behave more like aluminium
(iii) The 'silver' UK coins are made of $\mathrm{Cu} / \mathrm{Ni}$ alloy
(iv) The maximum oxidation state exhibited by Neptunium is +7
(i) (iii) only
(ii) (iv) only
(i) (iii) (iv) only
(i) (ii) (iii) only
Solution
$\mathrm{V}^{2+}$ is a strong reducing agent and liberates hydrogen from a dilute acid. Thus, (i) is correct.
In chemical behaviour, the earlier members of the lanthanide series behave more like calcium. Thus, (ii) is incorrect.
Silver $\mathrm{UK}$ coins $=\mathrm{Cu}+\mathrm{Ni}$ alloy.
Thus, (iii) is correct.
Neptunium (Np) belongs to the actinides series and has the configuration $5 \mathrm{f}^4 6 \mathrm{~d}^{1 \cdot} 7 \mathrm{~s}^2$ because of which it can show a maximum of +7 oxidation state.
Thus, (iv) is correct.