Chapter 7: Problem 40

\(\mathrm{K}^{+}\)and \(\mathrm{H}^{+}\)ions are present in an electrolyte. Which would get discharged at cathode? Why?

Short Answer

Expert verified

Answer: The ion that will be discharged at the cathode is the potassium ion, \(\mathrm{K}^{+}\), as it has a lower reduction potential compared to the hydrogen ion, \(\mathrm{H}^{+}\). The lower reduction potential means that \(\mathrm{K}^{+}\) has a higher tendency to be reduced (gain electrons) than \(\mathrm{H}^{+}\) at the cathode.

Step by step solution

Understand the basic principles of electrolysis

During the process of electrolysis, a direct current flows through an ionic compound in a molten or aqueous state. The positively charged ions (cations) are attracted to the negatively charged electrode (cathode), leading to their discharge at the cathode through reduction reactions.

Identify the electrode potentials of \(\mathrm{K}^{+}\) and \(\mathrm{H}^{+}\) ions

To determine which ion is more likely to undergo reduction and be discharged at the cathode, we need to compare the standard electrode potentials of these ions. Standard electrode potentials are the potentials of their half-cell reactions under standard conditions. The standard reduction potentials (E°) of the two ions are: - \(\mathrm{K}^{+}\): \(\mathrm{K}^{+} + \mathrm{e}^{-} \rightarrow \mathrm{K}\) (E° = -2.93 V) - \(\mathrm{H}^{+}\): \(2\mathrm{H}^{+} + 2\mathrm{e}^{-} \rightarrow \mathrm{H}_{2}\) (E° = 0.00 V)

Compare the electrode potentials and determine the ion to be discharged at the cathode

During the process of electrolysis, the ion with a lower reduction potential will be discharged at the cathode, as it is more likely to undergo reduction. Comparing the reduction potentials of \(\mathrm{K}^{+}\) (-2.93 V) and \(\mathrm{H}^{+}\) (0.00 V), we find that the reduction potential of \(\mathrm{K}^{+}\) is lower.

Explain the reason for the ion being discharged at the cathode

Since \(\mathrm{K}^{+}\) has a lower reduction potential, it is more likely to undergo reduction and be discharged at the cathode compared to \(\mathrm{H}^{+}\). The reason for this is that the reduction potential of an ion describes its tendency to get reduced (gain electrons). The lower the reduction potential, the higher the tendency of the ion to be reduced. In this case, \(\mathrm{K}^{+}\) has a higher tendency to be reduced than \(\mathrm{H}^{+}\), so it would get discharged at the cathode. Thus, the ion that will be discharged at the cathode is the potassium ion, \(\mathrm{K}^{+}\).

Unlock Step-by-Step Solutions & Ace Your Exams!

Full Textbook Solutions
Get detailed explanations and key concepts
Unlimited Al creation
Al flashcards, explanations, exams and more...
Ads-free access
To over 500 millions flashcards
Money-back guarantee
We refund you if you fail your exam.

Start your free trial

Over 30 million students worldwide already upgrade their learning with Vaia!

Recommended explanations on Chemistry Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

\(\mathrm{K}^{+}\)and \(\mathrm{H}^{+}\)ions are present in an electrolyte. Which would get discharged at cathode? Why?

Short Answer

Step by step solution

Understand the basic principles of electrolysis

Identify the electrode potentials of \(\mathrm{K}^{+}\) and \(\mathrm{H}^{+}\) ions

Compare the electrode potentials and determine the ion to be discharged at the cathode

Explain the reason for the ion being discharged at the cathode

One App. One Place for Learning.

Most popular questions from this chapter

Recommended explanations on Chemistry Textbooks

Chemical Analysis

Inorganic Chemistry

Organic Chemistry

Physical Chemistry

Chemical Reactions

Making Measurements

Study anywhere. Anytime. Across all devices.