Question

Which of the following statements is true for an electrochemical cell?
(a) Hydrogen is the anode and Copper is the cathode.
(b) Hydrogen is the cathode and Copper is the anode.
(c) Reduction occurs at the Hydrogen electrode.
(d) Oxidation occurs at the Copper electrode.

Answer 1

Hint: An electrochemical cell is a device apt for yielding electrical energy from chemical reactions or for utilising electrical energy to bring about chemical reactions. Redox reactions i.e, oxidation and reduction reactions both ensue simultaneously in these cells.

Complete Step by Step Solution:
We know that oxidation is defined as the process by which the loss of electrons happens. Oxidation happens at the anode. Reduction is the process by which the gain of electrons happens. Reduction happens at the cathode.If one among hydrogen or copper has a quite higher inclination to get reduced, then it will gain electrons. As a result, it will generate a negative charge with respect to the solution.

Likewise, if one among hydrogen or copper has a fairly higher preference to get oxidised, then it will lose electrons. This tendency for the loss or gain of electrons is called electrode potential. It is measured by relating it to the standard hydrogen electrode. The standard reduction potential of hydrogen is 0 volt. So, hydrogen can not undergo reduction. It will undergo oxidation which occurs at the anode. So, hydrogen is the anode.

By sign convention, a positive oxidation potential value means oxidation will occur. Positive reduction potential means reduction will occur. If reduction happens at an electrode with respect to standard hydrogen potential, then it is a reduction potential. The standard reduction potential of Copper is 0.52. It is a positive value. So, copper will undergo a reduction. So, the copper is the cathode.
So, option A is correct.

Note: Oxidation is specified as the method by which the loss of electrons happens.
Reduction is the method by which the gain of electrons occurs. This preference to either lose or gain electrons is called electrode potential. Positive oxidation potential means oxidation will occur. Positive reduction potential means reduction will take place.