If the cell potential is proportional to work and the standard reduction potential for the hydrogen ion is zero, does this mean that the reduction of the hydrogen ion requires no work?

Short Answer

Expert verified
In conclusion, the zero standard reduction potential for hydrogen ions does not necessarily mean that the reduction of the hydrogen ion requires no work. The cell potential, which is proportional to the work done, depends on the difference in standard reduction potentials between the two half-reactions involved (one being reduced and the other being oxidized). Therefore, depending on the relative reduction potential of the other species in the cell, the overall cell potential can still be positive, and work can be done during the reaction.

Step by step solution

01

Understand the concept of cell potential and its relation to work

Cell potential is the driving force that causes a chemical reaction to proceed spontaneously in an electrochemical cell. It is related to the electrical work done during the reduction process, which is the movement of electrons from one species to another. The greater the cell potential, the more work can be done by the reaction.
02

Recall reduction potential

Reduction potential is a measure of the tendency of a chemical element or compound to be reduced, i.e., to gain electrons. It is denoted in volts (V) and is based on a standard system called standard reduction potentials. For any given redox reaction, the overall cell potential is determined by the difference in the standard reduction potentials of the half-reactions involved.
03

Relationship between cell potential and work

The cell potential is proportional to the electrical work done during the reaction. The equation relating them is: \(W = -nFE\) where W is the electrical work done, n is the number of moles of electrons involved, F is Faraday's constant (96,485 C/mol), and E is the cell potential. For the reaction to be spontaneous, the electrical work, and hence, the cell potential must be positive.
04

Consider the hydrogen ion reduction potential

The standard reduction potential for the half-reaction of hydrogen ion (H+), by convention, is set to zero: \(2H^+ (aq) + 2e^- \rightarrow H_2 (g)\), E° = 0 V
05

Analyzing the work done for hydrogen ion reduction

In an electrochemical cell, hydrogen ions getting reduced means that they are gaining electrons. Although the standard reduction potential for hydrogen ions is zero, it does not imply that no work is required for the reduction of hydrogen ions. The reason is that the cell potential depends on the difference in the standard reduction potentials of the two half-reactions involved - one being reduced (like hydrogen ion) and the other being oxidized. Depending on the relative reduction potential of the other species in the cell, the overall cell potential can still be positive, which means that work can be done during the reaction. In conclusion, the zero standard reduction potential for hydrogen ions does not necessarily mean that the reduction of the hydrogen ion requires no work. It depends on the other species involved in the redox reaction and their standard reduction potentials.

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Most popular questions from this chapter

Gold is produced electrochemically from an aqueous solution of \(\mathrm{Au}(\mathrm{CN})_{2}^{-}\) containing an excess of \(\mathrm{CN}^{-}\). Gold metal and oxygen gas are produced at the electrodes. What amount (moles) of \(\mathrm{O}_{2}\) will be produced during the production of \(1.00 \mathrm{~mole}\) of gold?

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A solution containing \(\mathrm{Pt}^{4+}\) is electrolyzed with a current of \(4.00 \mathrm{~A}\). How long will it take to plate out \(99 \%\) of the platinum in \(0.50 \mathrm{~L}\) of a \(0.010-M\) solution of \(\mathrm{Pt}^{4+}\) ?

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