Question

Which of the following is the best reducing agent in aqueous solution:

• A. oxygen
• B. sodium
• C. magnesium
• D. lithium

Answer 1

The correct option is D lithium

Lithium has small size and large heat of hydration. The hydration energy more than compensates the ionization energy. This results in high oxidation potential for Li. This increases the ease with which the following change occurs.

$Li\left(s\right)\to L{i}^{+}\left(aq\right)+e^{-}$

Due to this, lithium is the strongest reducing agents in aqueous solutions.

hence , option D is correct .