# Electrolytic Cell Problem - Can't calculate req'd voltage

• mburt
In summary, the standard reduction potentials of Ag+ and Cd2+ are +0.80 V and -0.40 V respectively. To decrease the mass of Ag(s) in the electrolytic cell reaction, a net voltage of +1.30 V is required, which is slightly higher than the calculated value of +1.20 V. This is because the calculation only liberates electrons from the metal, but does not proceed with the reaction.
mburt

## Homework Statement

What voltage must be applied to decrease the mass of Ag(s) in the electrolytic cell
reaction below?

2 Ag+(aq) + Cd(s) → 2 Ag(s) + Cd2+(aq)

## Homework Equations

Standard reduction potential of Ag+: Eo = +0.80 V
Standard reduction potential of Cd2+: Eo = -0.40 V

## The Attempt at a Solution

Since the question says that Ag(s) will lose mass, I assume it must be oxidized so I wrote the equation:

Ag(s) → Ag+ + e- where Eo = -0.80 V (Change sign,cause oxidation)

and therefore the reduction reaction is:

Cd2+ + 2e- → Cd(s) where Eo = -0.40 V (keep sign)

So the net voltage is : -1.20 V... so the req'd voltage to make this non-spontaneous reaction occur is +1.20 V.

But the answer in the answer key says the req'd voltage is +1.30 V. Note that this is a multiple choice question and the answer of +1.20 V was an option as well.

Thanks!

If you apply 1.2V that's not enough yet to force reaction, for that you need a little bit more.

Okay thanks, so the calculation just liberates electrons from the metal, but doesn't proceed with the reaction...so to removed actual mass from the object you need more voltage.

Thanks!

## 1. What is an electrolytic cell?

An electrolytic cell is a device that uses electrical energy to facilitate a chemical reaction. It consists of two electrodes (an anode and a cathode) immersed in an electrolyte solution. When an external voltage is applied, the anode becomes positively charged and the cathode becomes negatively charged, causing ions in the electrolyte to move towards the electrodes and undergo a chemical reaction.

## 2. What is the purpose of an electrolytic cell?

An electrolytic cell is used to produce or break down compounds through a process called electrolysis. It is commonly used in industries such as metal refining, electroplating, and production of chemicals.

## 3. How do I calculate the required voltage for an electrolytic cell?

The required voltage for an electrolytic cell can be calculated using the Nernst equation, which takes into account the concentration of ions in the electrolyte, the number of electrons involved in the reaction, and the temperature. It is important to note that the required voltage may also depend on factors such as the type of electrodes and the presence of impurities in the electrolyte.

## 4. Why am I having trouble calculating the required voltage for my electrolytic cell?

There could be several reasons for difficulty in calculating the required voltage for an electrolytic cell. Some common reasons include incorrect input of parameters, incomplete knowledge of the chemical reaction taking place, or failure to consider external factors such as temperature or impurities. It is important to carefully review all the variables and equations involved in the calculation.

## 5. How can I troubleshoot my electrolytic cell if I cannot calculate the required voltage?

If you are having trouble calculating the required voltage for your electrolytic cell, it is recommended to double check all the parameters and equations used in the calculation. You can also consult with other scientists or experts in the field for their input. Additionally, performing experiments with different variables and comparing the results can help troubleshoot any issues with the electrolytic cell.

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