Question

A certain half-reaction has a standard reduction potential -1.33V . An engineer proposes using this half-reaction at the anode of a galvanic cell that must provide at least 0.70V of electrical power. The cell will operate under standard conditions.
a. Is there a minimum standard reduction potential that the half-reaction used at the cathode of this cell can have?b. Is there a maximum standard reduction potential that the half-reaction used at the cathode of this cell can have?

Answer 1

Answer:

a. -0.63 V

b. No

Explanation:

Step 1: Given data

• Standard reduction potential of the anode (E°red): -1.33 V

• Minimum standard cell potential (E°cell): 0.70 V

Step 2: Calculate the required standard reduction potential of the cathode

The galvanic cell must provide at least 0.70V of electrical power, that is:

E°cell > 0.70 V    [1]

We can calculate the standard reduction potential of the cathode (E°cat) using the following expression.

E°cell = E°cat - E°an   [2]

If we combine [1] and [2], we get,

E°cat - E°an > 0.70 V

E°cat > 0.70 V + E°an

E°cat > 0.70 V + (-1.33 V)

E°cat > -0.63 V

The minimum E°cat is -0.63 V and there is no maximum E°cat.