Strongest reducing agent among the following is I. Na^++e^- longrightarrow Na(s) E^°=-2.71 ~V II. Al^3++3 e^- longrightarrow Al(s) E^°=-1.66 ~V III. F_2(g)+2 e^- longrightarrow 2 ~F^- E^°=+2.87 ~V IV. 2 H_2 O+2 e^- longrightarrow H_2(g)+2 OH^-(a q); E^°=-0.83 ~V

Q10 / 180 · COMEDK 2015 · Chemistry

Strongest reducing agent among the following is I. $\mathrm{Na}^{+}+e^{-} \longrightarrow \mathrm{Na}(s) \quad E^{\circ}=-2.71 \mathrm{~V}$ II. $\mathrm{Al}^{3+}+3 e^{-} \longrightarrow \mathrm{Al}(s) \quad E^{\circ}=-1.66 \mathrm{~V}$ III. $\mathrm{F}_{2}(g)+2 e^{-} \longrightarrow 2 \mathrm{~F}^{-} \quad E^{\circ}=+2.87 \mathrm{~V}$ IV. $2 \mathrm{H}_{2} \mathrm{O}+2 e^{-} \longrightarrow \mathrm{H}_{2}(g)+2 \mathrm{OH}^{-}(a q); \quad E^{\circ}=-0.83 \mathrm{~V}$

Lower the $E^{\circ}$ value (more negative), stronger is the reducing agent. $\therefore \mathrm{Na}^{+}$is the strongest reducing agent.

Hence, the correct answer is option: 'D'.