Log out Go to App
Go to App

Learning Materials

Features

Discover

Chapter 20: Problem 33

(a) Write the half-reaction that occurs at a hydrogen electrode in acidic aqueous solution when it serves as the cathode of a voltaic cell.(b) Write the half-reaction that occurs at a hydrogen electrode in acidic aqueous solution when it serves as the anode of a voltaic cell. (c) What is standard about the standard hydrogen electrode?

Short Answer

Expert verified
The half-reaction for a hydrogen electrode when it acts as a cathode in acidic aqueous solution is: \[ 2H^{+}(aq) + 2e^{-} \rightarrow H_{2}(g) \] The half-reaction for a hydrogen electrode when it acts as an anode in acidic aqueous solution is: \[ H_{2}(g) \rightarrow 2H^{+}(aq) + 2e^{-} \] The standard hydrogen electrode (SHE) serves as a reference electrode and is maintained under these specific conditions: 1 M concentration of H+ ions, 1 atm pressure of H2 gas, and 25°C temperature.

Step by step solution

01

Understanding Redox Reactions

A redox reaction involves two half-reactions: one for the reduction process and one for the oxidation process. The substance that gains electrons is reduced, while the substance that loses electrons is oxidized. Step 2: Writing the half-reaction for a hydrogen electrode when it acts as a cathode
02

Writing the half-reaction for a hydrogen electrode when it acts as a cathode

When the hydrogen electrode is acting as a cathode, it will undergo a reduction reaction. In acidic aqueous solution, hydrogen ions (H+) will gain electrons to form hydrogen gas (H2). The half-reaction can be written as follows: \[ 2H^{+}(aq) + 2e^{-} \rightarrow H_{2}(g) \] Step 3: Writing the half-reaction for a hydrogen electrode when it acts as an anode
03

Writing the half-reaction for a hydrogen electrode when it acts as an anode

When the hydrogen electrode is acting as an anode, it will undergo an oxidation reaction. In acidic aqueous solution, hydrogen gas (H2) will lose electrons to form hydrogen ions (H+). The half-reaction can be written as follows: \[ H_{2}(g) \rightarrow 2H^{+}(aq) + 2e^{-} \] Step 4: Understanding the standard hydrogen electrode
04

Understanding the standard hydrogen electrode

The standard hydrogen electrode (SHE) is used as a reference electrode in electrochemical cells. The conditions for the standard hydrogen electrode are defined as follows: 1. The concentration of hydrogen ions (H+) in aqueous solution is 1 M (1 mol/dm³). 2. The pressure of hydrogen gas (H2) is 1 atmosphere (1 atm). 3. The temperature is 25°C (298K). By maintaining these specific conditions, the SHE can be used as a reference to measure the electromotive force (EMF) of other electrodes and redox reactions.

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!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

A voltaic cell is constructed that is based on the following reaction: $$ \mathrm{Sn}^{2+}(a q)+\mathrm{Pb}(s) \longrightarrow \mathrm{Sn}(s)+\mathrm{Pb}^{2+}(a q) $$ (a) If the concentration of \(\mathrm{Sn}^{2+}\) in the cathode half-cell is 1.00\(M\) and the cell generates an emf of \(+0.22 \mathrm{V},\) what is the concentration of \(\mathrm{Pb}^{2+}\) in the anode half-cell? (b) If the anode half-cell contains \(\left[\mathrm{SO}_{4}^{2-}\right]=1.00 M\) in equilibrium with \(\mathrm{PbSO}_{4}(s),\) what is the \(K_{s p}\) of \(\mathrm{PbSO}_{4} ?\)

(a) What is electrolysis? (b) Are electrolysis reactions thermodynamically spontaneous? (c) What process occurs at the anode in the electrolysis of molten \(\mathrm{NaCl}\) (d) Why is sodium metal not obtained when an aqueous solution of NaCl undergoes electrolysis?

(a) What is the definition of the volt? (b) Do all voltaic cells produce a positive cell potential?

A disproportionation reaction is an oxidation-reduction reaction in which the same substance is oxidized and reduced. Complete and balance the following disproportionation reactions: $$ \begin{array}{l}{\text { (a) } \mathrm{Ni}^{+}(a q) \longrightarrow \mathrm{Ni}^{2+}(a q)+\mathrm{Ni}(s)(\text { acidic solution })} \\ {\text { (b) } \operatorname{MnO}_{4}^{2-}(a q) \longrightarrow \mathrm{MnO}_{4}^{-}(a q)+\mathrm{MnO}_{2}(s) \text { (acidic }} \\ \quad {\text { solution) }} \\\ {\text { (c) } \mathrm{H}_{2} \mathrm{SO}_{3}(a q) \longrightarrow \mathrm{S}(s)+\mathrm{HSO}_{4}^{-}(a q)(\text { acidic solution })} \\ {\text { (d) } \mathrm{Cl}_{2}(a q) \longrightarrow \mathrm{Cl}^{-}(a q)+\mathrm{ClO}^{-}(a q) \text { (basic solution) }}\end{array} $$

A voltaic cell is constructed that uses the following reaction and operates at \(298 \mathrm{K} :\) $$ \mathrm{Zn}(s)+\mathrm{Ni}^{2+}(a q) \longrightarrow \mathrm{Zn}^{2+}(a q)+\mathrm{Ni}(s) $$ (a) What is the emf of this cell under standard conditions? (b) What is the emf of this cell when \(\left[\mathrm{Ni}^{2+}\right]=3.00 M\) and \(\left[\mathrm{Zn}^{2+}\right]=0.100 \mathrm{M} ?(\mathbf{c})\) What is the emf of the cell when \(\left[\mathrm{Ni}^{2+}\right]=0.200 \mathrm{M}\) and \(\left[\mathrm{Zn}^{2+}\right]=0.900 \mathrm{M} ?\)
See all solutions

Recommended explanations on Chemistry Textbooks

Chemical Analysis

Read Explanation

Kinetics

Read Explanation

Ionic and Molecular Compounds

Read Explanation

Organic Chemistry

Read Explanation

Inorganic Chemistry

Read Explanation

Making Measurements

Read Explanation
View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.

Sign-up for free