Question

In group Ia of alkali metals, the ionization potential decreases down the group. Therefore, lithium is a:

• A. good reducing agent
• B. poor reducing agent
• C. good oxidising agent
• D. poor oxidising agent

Answer 1

Answer: (A)

good reducing agent

Alkali metals are very good reducing agents because of their great tendency to lose electrons. The reducing character increases from Na to Cs.

However, Li is a stronger reducing agent than Na due to greater hydration energy.

Lithium being small in size has high ionization enthalpy. On the other hand, because of the small size, it is extensively hydrated and has very high hydration enthalpy. This high hydration enthalpy compensates the high energy needed to remove an electron. Thus Li has a greater tendency to lose electrons in solution than other alkali metals. Thus, Li is the strongest reducing agent.

Hence, the correct option is $\text{A}$