Test: Cells and Electrode Potential - JEE MCQ

The standard potential of hydrogen electrode is assumed to be zero at all temperature.

The Standard hydrogen electrode (abbreviated SHE), is a redox electrode which forms the basis of the thermodynamic scale of oxidation-reduction potentials. Its absolute electrode potential is estimated to be 4.44 ± 0.02 V at 25 °C, but to form a basis for comparison with all other electrode reactions, hydrogen's standard electrode potential (E⁰) is declared to be zero volts at all temperatures.

The solutions in which the electrodes are immersed are called electrolytes. The chemical reaction that takes placein a galvanic cell is the redox reaction. One electrode acts as anode in whichoxidation takes place and the other acts as the cathode in which reductiontakes place.the half-cell occurs is called reduction half-cell and the reaction taking place in it is called reduction half-cell reaction. The electrode where oxidation occurs is called anode and the electrode where reduction occurs is termed cathode. Electrons flow from anode to cathode in the external circuit.

The standard potential of hydrogen electrode is assumed to be zero at all temperature.

The Standard hydrogen electrode (abbreviated SHE), is a redox electrode which forms the basis of the thermodynamic scale of oxidation-reduction potentials. Its absolute electrode potential is estimated to be 4.44 ± 0.02 V at 25 °C, but to form a basis for comparison with all other electrode reactions, hydrogen's standard electrode potential (E⁰) is declared to be zero volts at all temperatures.

Reduction potential of fe is more than that of cr, so fe will reduce and act as cathode and cr will act as anode. now emf of cell is reduction potential of cathode - reduction potential of anode. so EMF= -0.45-(-0.75) = 0.3 V

The given order of reduction potentials (or tendencies) is Z > Y > X. A spontaneous reaction will have the following characteristics Z reduced and Y oxidised Z reduced and X oxidised Y reduced and X oxidised Hence, Y will oxidise X and notZ.

From the given data we find is strongest oxidising agent. More the positive value of , more is the tendency to get oxidized. Thus correct option is (c).

At infinite dilution, when dissociation is complete each ion makes a definite contribution towards molar conductance of the electrolyte irrespective of the nature of the other ion with which it is associated and that the molar conductance of any electrolyte at infinite dilution is given by the sum of the contributions of two ions. This is called Kohlrausch's law.

are molar ionic conductance at infinite dilution for cations and anions, respectively.

Since oxidation potential of is highest hence strongest reducing agent.

Given
and






So, reaction will take place.