Questions tagged [electrochemistry]
The branch of chemistry that deals with the study of redox reactions and how they can be applied to generate electricity (in electrochemical cells) and to carry out non-spontaneous reactions using electricity (electrolysis).
1,182
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Unknown salt formed from electrolysis of urine
I am not sure what I was expecting to happen with this but I created a circuit to electrolyze various household liquids. My electrodes are copper — or at least claim to be, I think they might just be ...
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2answers
104 views
Oxidation of metals/halogens by oxygen gas in acidic aqueous solution
I had some confusion about the correct answer to the following question:
Which substance can be oxidized by $\ce{O2(g)}$ in acidic aqueous solution?
Two of the answer choices were metal cations (...
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Still taught to reverse oxidation half cells in electrochemistry?
In a question, Oxidation of metals/halogens by oxygen gas in acidic aqueous solution, there was a point made that reduction half-cells should not be reversed.
I was taught ($\approx 1970$) in the ...
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135 views
What is the ideal temperature and pressure to crack water?
Using sun mirrors and solar cells for electricity. What temperature, pressure and voltage ideal for cracking water.
Source: NPR
Source
Would it take more or less electricity to crack water under ...
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37 views
Metal that does not deposit silver (Ag)
Hi Chemistry enthusiasts!
I am working on my scholarship exam practice but I am considered myself as a newbie so I would like to hear your opinion :)
From (1)-(4) below choose the metal that does ...
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28 views
Calculate chemical potentials to find electrode Fermi level
I'm running some simple simulations of the semiconductor-electrolyte interface and I'm having a hard time figuring out the equilibrium condition. Can someone please help me with my electrochemical ...
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2answers
376 views
Using a calcium metal anode in aqueous solution?
In school, I am doing an electrochemistry lab in which I need to create a galvanic cell battery with the highest voltage possible using two beakers, a salt bridge, and electrodes.
To maximize the ...
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3answers
158 views
What is the flow of electrons, cations, and anions in a voltaic cell (please see image attached)?
This is an IB question. The mark scheme says that the correct answer is A and only A. But I believe B is also correct. The following is my thought process. Since A is more reactive, it undergoes ...
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2answers
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For Hess' law type questions, when do you take the inverse of the constant and when do you switch the sign?
For example, when you're given the enthalpy $\Delta H$ of a reaction and you want to switch that reaction around in order to add it to something else, you switch the sign. Furthermore, when adding ...
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3answers
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What is the difference between molar conductance and molar conductivity?
I'm learning (or at least trying to learn) about electrochemistry, but a major obstacle to that, is that different books I refer use different terms for the same symbols. So in a last ditch attempt to ...
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1answer
45 views
Would electrolysis work with a conductive (but waterproof) divider between anode and cathode?
Note I am not trying to "double fuel efficiency" in a car or something scamey like that. My purpose is to fill balloons with hydrogen and possibly power an HHO torch (also make it safer because pure ...
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236 views
[Co(H2O)6]3+ vs [Co(NH3)6]3+ oxidising water
Cobalt(III) complexes cannot be prepared by addition of the ligand to a solution of the metal cation because the aqua cation $\ce{[Co(H2O)6]^3+}$ has no stable existence in solution. It is strongly ...
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48 views
What do electrons usually do when lead acid battery is idle?
Lead acid batteries operation are governed by Redox reactions for charging and discharging. But, what do electrons usually do when lead acid battery is idle? And why?
Assumptions:
Say more ...
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109 views
Reduction Potentials [closed]
Standard electrode potential values can be used to judge the reducing ability of a metal. When I was introduced to this topic a simple picture was painted: you put a metal into a solution of its ions. ...
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3answers
86 views
Confusion on electrode potentials
Standard electrode potential values can be used to judge the reducing ability of a metal. When I was introduced to this topic a simple picture was painted: you put a metal into a solution of its ions. ...
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1answer
270 views
When surface area of electrodes is increased, why does the current in the galvanic cell increase?
I did a lab in galvanic cells where I changed the surface area. As a result, the current increased, but I don't really understand why. I guessed it was because more are means that more ions from the ...
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1answer
46 views
What are the products in the reaction of sulphuric acid and Group 2 metals?
When group 2 metals, says magnesium, is reacted with nitric acid, oxide of nitrogen is produced beside hydrogen gas. The standard electrode potential values agree with this:
$$
\begin{align}
\ce{Mg^...
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27 views
What is the reasoning behind deriving electrode potential of a metal-metal sparingly soluble salt electrode?
Considering a sparingly soluble salt $M_xN_y$ of the metal $M$, in which the corresponding reaction is $M_xN_y$ = $xM^{y+}$ + $yN^{x-}$,
the standard electrode potential is given by
$E^{o}_{M_xN_y/M/...
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70 views
Does increasing the concentration of the anode electrolyte in a galvanic cell increase or decrease the voltage produced
Im in kind of a pickle here. I am using nernst equations to calculate the theoretical voltage produced for different concentrations of $\ce{Al(NO3)3}$.
Reaction: $$\ce{2Al(s) + 3Pb^{2+}(aq)⟶2Al^{3+}(...
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1answer
213 views
Does higher Oxidation/ reduction potential translate to higher energy storage in battery?
Some articles refer to the fact that Lithium is preferred metal of choice for batteries because their half cell voltage is high (slightly above 3V)
If that is the case why can't we use other metals ...
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What are the reasons that make platinum a good electrocatalyst for oxygen reduction reaction? [duplicate]
Researchers are trying to find new electrocatalysts for energy related reactions in fuel cells in order to replace the expensive platinum-based materials.
I would like to know what are exactly the ...
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40 views
Where does Free Energy go in a Redox Reaction?
This doubt came to my mind while answering the following question:
Why does a voltaic cell not operate unless the two separate compartments are connected by an external circuit?
The answer seems ...
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3answers
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No sign flipping while figuring out the emf of voltaic cell?
I learnt that for a voltaic cell, the value for the $E_\text{cell}^\circ$ when the reaction is spontaneous is given by
$$E_\text{cell}^\circ = E_\text{cathode}^\circ - E_\text{anode}^\circ, \label{...
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1answer
68 views
Intensive and Extensive Properties--Resistance
Is resistance an intensive quantity or an extensive one? And why?
Let me present 2 scenarios.
Resistance of a wire:
The resistance of a wire depends on area and length. This implies it depends on the ...
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1answer
174 views
Does electrolysis of aqueous tin(II) chloride produce Cl₂, SnCl₄ or both?
When applying a current to an aqueous solution of tin(II) chloride, tin crystals grow from the cathode. However, I'm not sure about the anode. It seems like there are two possible reactions:
$$\ce{2 ...
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28 views
Oxidation states of Cu in YBa2Cu3O6 based on crystal structure [duplicate]
How does on go about this? I understand There is a +5 charge distributed on 3 copper ions. So either we have 2+, 2+ and 1+ or 3+, 1+, and 1+. Judging from the structure there are to unequivalent types ...
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1answer
43 views
Can gold cause tin or other metals to corrode?
I stumbled upon the following article while trying to identify some old RAM modules:
https://www.techrepublic.com/article/quickly-identify-ram-chips-with-these-tips/
In the article, it mentions the ...
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5answers
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Why don't the electrons move through the electrolyte (instead of the circuit) in a galvanic cell?
I was learning about galvanic cells and I had a problem understanding why electrons do not travel through the electrolyte solutions themselves, instead preferring to travel through metals. Can ...
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1answer
30 views
Which ions determine ionic conductivity of a salt solution?
Let's take $\ce{ZnSO4}$ salt solution in water for example. So the ions inside my solution will be $\ce{H+}$, $\ce{OH-}$, $\ce{Zn^2+}$ and $\ce{SO4^2-}$.
My questions are:
Is the ionic conductivity ...
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What happens electrochemically when bird droppings corrode cars?
I think the metal of the car first goes through an acid corrosion, followed by an electrochemical corrosion. First, the uric acid in bird poop corrodes with iron: 2Fe+C5H4N4O3 -> C5N4O3Fe2+2H2. Then, ...
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Can CO2 Be Electrochemically Reduced to Carbon Nanotubes?
Mitigation of CO2 as greenhouse gas has driven increasing investigation of its chemical reduction. The 2018 paper "Recent Progress in the Theoretical Investigation of Electrocatalytic Reduction of CO2"...
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1answer
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Adding Standard Reduction Potentials
I am working the following USNCO problem (#41 from 2002). Based on this question and answer Deriving a reduction potential from two other reduction potentials, it seems that $\Delta G$ must be ...
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2answers
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How to determine the potential of a cadmium zinc cell under standard conditions?
I write the half-equations:
\begin{align}
\ce{Zn &<=> Zn^2+ + 2e^-}& E^\circ &= +0.763~\pu{V}\\
\ce{Cd^2+ + 2e- &<=> Cd}& E^\circ &= +0.403~\pu{V}
\end{align}
In ...
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1answer
3k views
Why does the Co³⁺/Co²⁺ couple have such a high reduction potential?
Cobalt is changing from $\mathrm{(3d)^6}$ to $\mathrm{(3d)^7}$ electronic configuration. What's so stabilizing about that? Just by reduction potentials this couple is more oxidising than hydrogen ...
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1answer
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Cobalt electroplating over nickel-plated steel
From my research, I understand that cobalt can be used on top of a nickel layer to improve durability of the nickel plating on a steel object.
I am using a nickel anode and nickel acetate as ...
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1answer
47k views
Does concentration of salt increase or decrease rate of rusting?
I want to know whether increasing the concentration of salt, specifically $\ce{NaCl}$, increases or decreases the rate of rusting. There are conflicting theories that explain opposite outcomes:
...
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Solutions when Electroplating
I'm essentially conducting an experiment to see whether using different copper-based compounds when electroplating copper onto an iron nail would give different results.
So far, I've used copper ...
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Why does chromium metal not react with a solution of Mg^2+ even though their standard cell potentials produce a net positive voltages?
Write net equations for the spontaneous redox reactions that occur during the following or NONE if there is no extensive reaction. Use the lowest possible coefficients. Include states-of-matter under ...
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Calculating Solubility Product of AgCl from electrode potential
I have to use a measured electrode potential to find the solubility product of $\ce{AgCl}$. In our experiment, we first mixed one drop of $\pu{1.0 M}$ $\ce{AgNO3}$ with $\pu{10 mL}$ of $\pu{1.0 M}$ $\...
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How to calculate the cell potential after the reaction has operated long enough for the Fe2+ to have changed by some concentration?
Consider the cell described below at $\pu{261 K}$:
$$\ce{Fe | Fe^2+ (\pu{0.925 M}) || Cd^2+ (\pu{0.981 M}) | Cd}$$
Given $E^\circ_\ce{Cd^2+ -> Cd} = \pu{-0.403 V}$, $E^\circ_\ce{Fe^2+ -&...
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Is the 'n' in Delta G = -nFE, ever negative?
Is it possible for $n$ in $\Delta G=-nFE$ to ever be negative? Trying to figure out where I went wrong on some thing and want to rule that out.
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154 views
Difference between electrode potential and standard electrode potential
I was studying electrochemistry but the thing that confused me was that what is the basic difference between electrode potential and standard electrode potential?
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2answers
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Is basic solution an electrode?
Question:
Calculate the potential of hydrogen electrode in contact with a solution of pH 10.
My attempt:
Cell reaction: $\ce{ H^+ + e^- -> \frac{1}{2}H_2 }$
I've attempted to solve this ...
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2answers
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Determination of solubility equilibrium using galvanic cell reactions
This is the problem:
We can determine the solubility equilibrium for silver bromide using cell:
Ag (s) | AgNO3 (aq) || KBr (aq) | AgBr (s) | Ag (s)
We know that:
$\text{AgBr} + \text{e}^- \...
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1answer
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How to use Kohlrausch's law with ionic equivalent conductances? [closed]
My text says that for an ionic compound like AxByif ionic equivalent conductance of Ay+ is a and that of Bx- ion is b, then the equivalent conductance for AxBy would be a/y + b/x
Now my question is:...
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1answer
68 views
Do the salt bridge ions have to match the ions in the half-cells solutions?
Does the salt bridge in a galvanic cell have to have the same ions as the ones in the solutions? E.g. does it need to have nitrate ions if the half-cells contain copper nitrate and zinc nitrate, or ...
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1answer
33 views
Measuring bioanode potential against Ag/AgCl reference electrode
I'm trying to make a bioanode for use in a microbial fuel cell. I have a piece of carbon cloth in an acetate solution with river sediment. I'd like to know the potential of the anode, so I connected ...
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62 views
Why do reference electrodes have porous frits or membranes as a salt bridge?
From what I understand, they act as a salt bridge between the reference electrode electrolyte and the analyte solution (in a potentiometric titration). But why do we use partially permeable membranes ...
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2answers
102 views
Is it possible to build a non-degrading battery?
I am not a chemist, nor do I know anything about chemistry. What I am interested in are batteries. I don't really care about the whole "Charge in minutes, last for days" types of batteries (the ...
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Instead of using an Ag/AgCl electrode, can I simply use another beaker and connect it to my solution via a salt bridge? [closed]
I'm trying to perform a potentiometric titration as part of my high school laboratory work, by reducing iron(III) to iron(II), and measuring the voltage change as I add cobalt(II) (to reduce it).
The ...
