Question

Which of the following has the highest reduction potential?

• A.
• B.
• C.
• D.

Answer 1

The correct option is A

This is an anomalous property of Li as described by the diagram below: $\Delta H_{net}=\Delta H_{sub}+\Delta H_{Hion}+\Delta H_{hyd}$ For spontaneous reactions, $\Delta H_{net}$ must be negative which is possible only if $\Delta H_{hyd}$ is a large negative value. This happens only in case of Li due to its small size.