Question

The standard reduction potential, E’°, of any redox pair is defined for the half-cell reaction:

Oxidizing agent + n electrons → reducing agent

The E’° values for the NAD+/NADH and pyruvate/lactate conjugate redox pairs are -0.32 V and -0.19 V, respectively.

a) Which redox pair had the greater tendency to lose electrons? Explain.

Answer 1

The NAD+/NADH redox pair has a greater tendency to lose electrons compared to the pyruvate/lactate pair, as evidenced by its more negative standard reduction potential of -0.32 V.

Step-by-step explanation:

When comparing the standard reduction potentials (E’°) for the NAD+/NADH and pyruvate/lactate conjugate redox pairs, which are -0.32 V and -0.19 V respectively, one can determine the greater tendency to lose electrons (greater oxidizing strength) by examining the more positive E’° value.

The half-cell with the higher (less negative) reduction potential will undergo reduction, and the one with the lower (more negative) will undergo oxidation. In this case, the pyruvate/lactate pair with a reduction potential of -0.19 V has a lower tendency to lose electrons (is a weaker oxidizing agent) than the NAD+/NADH pair with a reduction potential of -0.32 V. Consequently, the NAD+/NADH redox pair has the greater tendency to lose electrons.