Problem: An electrochemical cell (battery) consists of a Cu plate immersed in 100 mL of 0.055 M Cu2+ solution and a Zn plate immersed in 100 mL of 0.550 M Zn2+ solution. The two compartments are connected by a salt bridge and the cell is maintained at 25 °C. The cell is discharged by passing a 10.00 mA current for 105 seconds.The standard reduction potentials are given below:Cu2+ (aq) + 2 e- → Cu (s)              ε°red = + 0.34 VZn2+ (aq) + 2 e- → Zn (s)               ε°red = - 0.76 VWhat are the concentrations of cations (Cu2+ and Zn2+) in the respective compartments after the discharge? Please circle your answer(s).

FREE Expert Solution

We are asked to calculate the concentrations of cations (Cu2+ and Zn2+) in the respective compartments after the discharge.


We go through the following steps to solve the problem: 

Step 1. Calculate the moles electrons transferred
Step 2. Calculate moles Zn2+ produced and and Cu2+ consumed
Step 3Calculate moles initially present
Step 4. Calculate new concentrations


Step 1. Calculate the moles electrons transferred


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Problem Details

An electrochemical cell (battery) consists of a Cu plate immersed in 100 mL of 0.055 M Cu2+ solution and a Zn plate immersed in 100 mL of 0.550 M Zn2+ solution. The two compartments are connected by a salt bridge and the cell is maintained at 25 °C. The cell is discharged by passing a 10.00 mA current for 105 seconds.

The standard reduction potentials are given below:

Cu2+ (aq) + 2 e- → Cu (s)              ε°red = + 0.34 V

Zn2+ (aq) + 2 e- → Zn (s)               ε°red = - 0.76 V

What are the concentrations of cations (Cu2+ and Zn2+) in the respective compartments after the discharge? Please circle your answer(s).