Question

1. A standard galvanic cell is constructed with F₂ | F^- and Hg²⁺ | Hg half cell compartments connected by a salt bridge. Which of the following statements are correct?

(Choose all that apply.)

A. The anode compartment is the F₂|F^- compartment.

B. As the cell runs, anions will migrate from the F₂|F^- compartment to the Hg²⁺|Hg compartment.

C. In the external circuit, electrons flow from the F₂|F^- compartment to the Hg²⁺|Hg compartment.

D. The anode compartment is the Hg²⁺|Hg compartment.

E. F₂ is reduced at the cathode.

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

(Choose all that apply.)

A. Mg²⁺|Mg could be the other standard half cell.

B. The cathode reaction is Cd -> Cd²⁺ + 2e^-.

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

D. Fe³⁺|Fe²⁺ could be the other standard half cell.

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

Answer 1

Answer:-

(1)-

As we know that a standard galvanic cell which is constructed with F₂ | F^- and Hg²⁺ | Hg half cell compartments connected by a salt bridge. The Hg²⁺ | Hg half cell acts as anode and  F₂ | F^- half cell acts as cathode because in standard electrode potential of Hg²⁺ | Hg is 0.85 V whereas standard electrode potential of F₂ | F^- is 2.87 V.

therefore

half cell reaction at anode :-

Hg Hg²⁺ + 2e^- ; (oxidation) ; E⁰_Hg/Hg²⁺ = 0.85 V

So cations (Hg²⁺) increased in anodic compartment

half cell reaction at cathode :-

F₂ +  2e^-   2F^- ; (reduction) ;  E⁰_F2/F^- = 2.87 V

So anions (F^- ) increased in cathodic compartment

So there would be of migration of cations form the anode i.e Hg²⁺|Hg compartment to cathode i.e F₂|F^- compartment.

Also we know that in galvanic cell electrons always flow from anode to cathode i.e Hg²⁺|Hg compartment to the F₂|F^- compartment.

therefore correct statements are as follows:-

D. The anode compartment is the Hg²⁺|Hg compartment.

E. F₂ is reduced at the cathode.

(2)-

As we know that a standard galvanic cell which is constructed with a Cd²⁺ | Cd half cell which acts as the cathode and its standard electrode potential is -0.40 V whereas other electrodes such as  Mg²⁺|Mg has standard electrode potential - 2.36 V and Fe³⁺|Fe²⁺ has standard electrode potential 0.77 V.

As mentioned above value of standard electrode potential of given electrodes only Mg²⁺|Mg electrode would be acts as anode when it is connected with Cd²⁺ | Cd half cell which acts as the cathode .

half cell reaction at anode :-

Mg Mg²⁺ + 2e^- ; (oxidation) ; E⁰_Mg/Mg²⁺ = - 2.36 V

So cations (Mg²⁺) increased in anodic compartment

half cell reaction at cathode :-

Cd²⁺ +  2e^-   Cd ; (reduction) ;  E⁰_Cd2+/Cd = -0.40 V

Also we know that in galvanic cell electrons always flow from anode to cathode i.e Mg²⁺|Mg compartment to the Cd²⁺ | Cd compartment.

therefore correct statements are as follows:-

A. Mg²⁺|Mg could be the other standard half cell.

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