Question

A standard galvanic cell is constructed in which a Cd²⁺ | Cd half cell acts as the cathode. Which of the following statements are correct?

Hint: Refer to a table of standard reduction potentials.

Cd2+ : -0.403 Fe3+ : 0.771

(Choose all that apply.)

___As the cell runs, anions will migrate from the Cd²⁺|Cd compartment to the other compartment.

___Cd is oxidized at the cathode.

___In the external circuit, electrons flow from the Cd²⁺|Cd compartment to the other compartment.

___Cd²⁺ is reduced at the cathode.

___The anode compartment could be Fe³⁺|Fe²⁺.

Answer 1

1.reaction at cathode is reduction

Cd²⁺ +2e--------->Cd

electron is released at anode and deposited at cathode.

so first statement is not applicable.as the cell runs anions reduces and deposited at the electrode as Cd.

2.at cathode reduction occurs. so this statement is also not applicable.

3.electron is used at Cd/Cd⁺² compartment.so electron cant flow from this compartment .this statement is also not applicable.

4.Cd⁺²​ is reduced at cathode to Cd.this is correct

5.

E⁰_cell =E_cathode - E_anode

deltaG=-nFE⁰_cell

to get a spontaneous cell reaction delta G should be negative.to get deltaG negative,E⁰_cell shoulb be positive.to achieve that

E_cathode should be higher value than E_anode.

and so here E⁰ of Fe³⁺ is higher than that of Cd²⁺.so Fe³⁺ is the cathode and Cd/Cd⁺² is anode

so this statement is false.Fe³⁺/Fe should be cathode .

ANS.Cd⁺²​ is reduced at cathode