Question

An electrochemical cell has the following standard cell notation.

Mg(s) | Mg^2+ (aq) || Aq^+(aq) | Aq(s)

What is the standard potential for the cell?

Is this a spontaneous or non spontaneous reaction? Explain your answer.

Is this a galvanic cell or an electrolytic cell? Explain your answer.

Answer 1

The cell notation is:

`Mg(s)|Mg^(+2)(aq)||Ag^(+)(aq)|Ag(s)`

here in cell notation the left side represent the anodic half cell where right side represents the cathodic half cell

in anodic half cell : oxidation takes place [loss of electrons]

in cathodic half cell: reduction takes place [gain of electrons]

1) this is a galvanic cell

2) the standard potential of cell will be obtained by subtracting the standard reduction potential of anode from cathode

`E^(0)_(Mg)=-2.38V`

`E^(0)_(Ag)=+0.80V`

Therefore

`E^(0)_(cell)=0.80-(-2.38)=+3.18V`

3) as the value of emf is positive the reaction will be spontaneous as the free energy change of reaction will be negative

Δ
`G^(0)=-nFE^(0)`

As reaction is spontaneous and there will be conversion of chemical energy to electrical energy it is a galvanic cell.