Answer to Question #108241 in General Chemistry for Matthew Mintzer

Question

Consider the following half reaction:
Na⁺(aq) + e⁻ → Na(s).
For this reaction, E°(red) = -2.7 V. If this reaction is tripled so that 3 Na⁺ ions are reduced to 3 Na atoms, what is the new E°(red)?

Answer 1

When adding up the electrode reactions, the potentials are added algebraically and their sum will be the electromotive force of the total reaction of the galvanic element.

Because ,E°(Na+/Na) = -2.7 V.

Na⁺(aq) + e⁻ → Na(s). x3

=>-2.7*3=-8.1