mercury-mercury(2) half cell and chlorine half cell.
reduction potential
The reduction potential of a half-cell reaction indicates the tendency of a species to gain electrons and undergo reduction. It is usually given in volts (V), relative to the standard hydrogen electrode (SHE) which is assigned a potential of 0 V.
The half-cell reaction for the reduction of mercury (II) ions (Hg2+) to elemental mercury (Hg) can be represented as:
Hg2+ + 2e- -> Hg
The standard reduction potential for this half-cell reaction is +0.85 V. This means that mercury (II) ions have a strong tendency to be reduced to elemental mercury, and the reaction is favorable under standard conditions.
The half-cell reaction for the reduction of chlorine gas (Cl2) to chloride ions (Cl-) can be represented as:
Cl2 + 2e- -> 2Cl-
The standard reduction potential for this half-cell reaction is +1.36 V. This means that chlorine gas has a strong tendency to be reduced to chloride ions, and the reaction is favorable under standard conditions.
It is important to note that in order to determine the overall cell potential or the potential difference between the two half-cells, the reduction potentials of both half-cell reactions need to be taken into account. By subtracting the reduction potential of the anode reaction (in this case chlorine reduction) from that of the cathode reaction (in this case mercury reduction), the overall cell potential can be calculated.