If the standard reduction potential of a 1/2 cell is positive, which redox rxn is spontaneous when paired?
Frank_Kay asked:
The whole question is “If the standard reduction potential of a half-cell is positive, which redox reaction is spontaneous when paired with a hydrogen electrode?”
the choices are:
A. Oxidation
B. Reduction
C. Both a and b
D. neither a nor b
Incoming search terms:
- half-cell alkaline
- why standard cell potential is positive the reaction go spontaneously
Answer is B.
For a reaction to be spontaneous, E must be positive for the sum of the oxidation half-reaction and the reduction half-reaction. You have a reduction reaction with a positive Eo. The hydrogen electrode has Eo=0. So combining the reduction reaction written in the forward direction, i.e. as a reduction reaction, with the hydrogen electrode gives Eo>0.