Question

A voltaic cell is constructed in which the following cell reaction occurs. The half-cell compartments are connected by a salt bridge.

question 1 - Sn²⁺(aq)+ Co(s) ----------> Sn(s)+ Co²⁺(aq)

The anode reaction (including states) is:

The cathode reaction (including states) is:

In the external circuit, electrons migrate _____fromto the Co|Co²⁺ electrode _____fromto the Sn|Sn²⁺ electrode.

In the salt bridge, anions migrate _____fromto the Sn|Sn²⁺ compartment _____fromto the Co|Co²⁺ compartment.

question 2 -

A voltaic cell is constructed in which the anode is a Cd|Cd²⁺ half cell and the cathode is a Cu⁺|Cu²⁺ half cell. The half-cell compartments are connected by a salt bridge.

Use the lowest possible coefficients.

The anode reaction (including states) is:

The cathode reaction (including states)is

The net cell reaction(including states) is:

In the external circuit, electrons migrate _____fromto the Cu⁺|Cu²⁺ electrode _____fromto the Cd|Cd²⁺electrode.

In the salt bridge, anions migrate _____fromto the Cd|Cd²⁺ compartment _____fromto the Cu⁺|Cu²⁺ compartment

Answer 1

1. The given reaction is

Sn²⁺ (aq) + Co (s) ----------> Sn (s) + Co²⁺ (aq)

The anode reaction is

Co (s) ---------> Co²⁺ (aq) + 2 e^-

The cathode reaction is

Sn²⁺ (aq) + 2 e^- ---------> Sn (s)

The above assignments are true because oxidation takes place at the anode and reduction takes place at the cathode.

In the external circuit, electrons migrate from the Co│Co²⁺ electrode to the Sn│Sn²⁺ electrode. This is because electrons always flow from the anode or the oxidation cell to the cathode or the reduction cell.

In the salt bridge anions migrate from the Sn│Sn²⁺ compartment to the Co│Co²⁺ compartment. The function of a salt bridge is to maintain electro-neutrality of the solutions. The oxidation reaction at the anode generates positively charged ions while the reduction at the cathode leads to an accumulation of negatively charged ions. In order to maintain electrical neutrality of the solutions, the anions move from the cathode compartment to the anode compartment.

2. The anode reaction is

Cd (s) ---------> Cd²⁺ (aq) + 2 e^-

The cathode reaction is

Cu²⁺ (aq) + 2 e^- ---------> Cu (s)

The net cell reaction is

Cd (s) + Cu²⁺ (aq) ----------> Cd²⁺ (aq) + Cu (s)

In the external circuit, the electrons migrate from the Cd│Cd²⁺ electrode (anode) to the Cu│Cu²⁺ electrode (cathode).

In the salt bridge, the anions migrate from the Cu│Cu²⁺ compartment to the Cd│Cd²⁺ compartment.