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).

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38 views

Where do the electrons in lead–acid battery come from? [closed]

$$ \begin{align} \ce{PbO2 + H2SO4 &-> PbSO4 + H2O + O} &\quad &\text{(anode)}\\ \ce{Pb + H2SO4 &-> PbSO4 + H2} &\quad &\text{(cathode)} \end{align} $$ The cathode’s $\ce{...
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Nernst equation for mixed cathode battery

What is the Nernst equation for a mixed cathode battery or a cell where there are multiple half reactions? I assume it is similar to unequal voltage connected in parallel? https://youtu.be/XoLzn49IZjM ...
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1answer
33 views

Contradiction in variation of conductance and conductivity on dilution

I do conceptually understand that on dilution conductivity decreases and conductance increases but if we look at the formula of conductivity, a contradiction seems to arise. $$\kappa=GG^*$$ where $\...
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Mass Transport and Ion Transport - Li-ion Batteries

I am new to the field and trying to grasp the theories/ physical phenomena behind the Li-ion batteries. I came across two phenomenons 'Mass transport' and 'Ion transport'. As I understood Mass ...
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3answers
148 views

Copper electrode in a Daniel cell

Suppose I have a beaker containing $\ce{CuSO4}$ solution and I dip $\ce{Cu}$ rod in it. What reactions are going to take place? Is the $\ce{Cu}$ rod going to acquire any positive charge? I am asking ...
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1answer
47 views

Why can't two 3° free radicals combine?

In Kolbe Electrolysis, my teacher told that when a 1° or 2° free radical is used, we get alkanes through dimerisation. Why wont dimerisation occur for a 3° one??
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Effect of charge density on electrolysis of dilute sulphuric acid

I am told that if electrolysis of dilute sulfuric acid is performed under high charge density, then the following reaction takes place at anode instead of evolving oxygen: $$\ce{2 HSO4- -> H2S2O8 +...
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1answer
49 views

Why does molar conductivity depend on the volume of the solution? [closed]

I have been searching the answer to this question everywhere and (almost) the only answer I get is to formula based: ‘Since molar conductivity = k / M = k/1/V for one mole = kV Therefore molar ...
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Did both temperature of nernst equation same

I saw the nernst equation I have a doubt.Did the temparature at which Standard potential is measured is also the temparature at which electrode potential is measured. I mean Did the temperature (T) in ...
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3answers
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Trying to understand the chemistry in an iron carbon battery

I am trying to understand the chemistry that occurs in an iron carbon battery during charging. The negative electrode is iron, the positive electrode is carbon. The electrolyte is iron(II) chloride. ...
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1answer
546 views

What is the meaning of signs in electrode potentials?

Question Suppose you have a cell set up between a copper metal/copper(II) ion electrode and a reference electrode. Under standard conditions, the emf of this cell was −0.07 V. The standard electrode ...
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1answer
51 views

Can I anodize an aluminum coating on steel to have better corrosion inhibition for the steel?

I am planning to coat aluminum on steel and I want to give the steel its maximum corrosion protection. Is anodizing the coating necessary?
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4answers
391 views

In NaCl electrolysis, why does chlorine ion get oxidized but not oxygen ion? [closed]

In $\ce{NaCl}$ electrolysis, on the positive electrode (aka. on the electrode where oxidation happens), $\ce{Cl-}$ ions were oxidized to $\ce{Cl2}$. But we don't see any $\ce{O^2-}$ at all. My pre-...
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1answer
2k views

Unit conversion of Molar Conductivity

I know this might be a silly question but I am confused with different answers of internet. My question is: Molar conductivity is given as: Molar conductivity = $\frac{\kappa}{M}$. S.I. unit of : $...
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1answer
3k views

What is the electrical conductivity of pool water?

What is the electrical conductivity of pool water? I tried to find some information, unfortunately without success. I need to know it to make an underwater electronic project.
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Salt concentration and electrical permittivity of water

We know that the electric flux density $D$ can be related to electric field intensity $E$ as $$D = \epsilon(\omega) E$$ where $$\epsilon(\omega) = \epsilon_0 \epsilon_r(\omega)$$ and $\epsilon_0$ ...
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2answers
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Does Copper reacts with Sodium Sulfate solution?

Okay I am trying to make a capacitor in which current collector is copper foil and electrolyte is sodium sulfate. Would this work? Do these two react with each other or not?
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4answers
165 views

What happens when a piece of copper is placed in 1M HCl?

I know that the answer is that nothing happens, but the explanation is confusing me in some places. Firstly, we are given that: \begin{align} \ce{Cl2 + 2e- &-> 2Cl-} & (E &= \pu{1.36 V})...
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Why is the concentration halved at the intersection of Hg²⁺/Hg₂²⁺?

For the couple $\ce{Hg^2+}/\ce{Hg2^2+}$: $E^\circ = \pu{0.91V}$. At the border the concentration is $c = \pu{0.10 mol \cdot L-1}$ for all ions. Hence build the stability diagram of mercury. I have: ...
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1answer
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What is the substance turning salty water green when electrolysed? [duplicate]

I am a student and I take O.L. Chemistry, in my knowledge I know if I electrolysed concentrated aqueous NaCl solution I should get Hydrogen evolved at the cathode and chlorine at the anode. I did an ...
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1answer
53 views

why does galvanic cell stop working when charge neutrality is not maintained? [closed]

In galvanic cell, salt bridge maintains charge balance between solutions. If there's no salt bridge, charge neutrality will be broken as solution(anode) becomes positive and that of cathode becomes ...
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1answer
142 views

Would a salt bridge work through which the ions could not diffuse into the half cells?

Instead of covering the ends of the salt bridge in an electrochemical cell with a membrane, one could also plug them on both sides with a conductive non-porous material, for example gold, which doesn'...
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Are the reactions in a simple cell overall exothermic? Why?

For context, I'm in high school. I'm trying to mentally connect electrolysis with the concept of energy changes and kinda having trouble. I understand the bottom line is that a simple cell converts ...
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195 views

Is there a potentiometric method for monitoring salt formation in organic solvent?

I work in a pharmaceutical R+D lab, and currently aim to develop a validatable potentiometric method for determining the optimal amount of acid to add to a basified small organic molecule for ...
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1answer
140 views

Why does increasing the concentration of the salt bridge in a galvanic/voltaic cell increase voltage?

I recently set up an experiment with 1M half cells made up of zinc and copper nitrate. They were connected with a sodium nitrate salt bridge of varying concentrations. As the concentration doubled 5 ...
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106 views

In a half cell reaction, Is the potential halfed?

If you have an electrolyte of $\ce{Zn^2+}$ and $\ce{SO4^2-}$ (Neutral) Then you dip in it a Zinc electrode. Zinc potential is $\pu{-0.74 V}$ (relative to SHE). So that means there is a $\pu{-0.74V}$ ...
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1answer
75 views

Reactions involved in Titanium Anodisation

I am writing up a lab report investigating titanium anodisation and producing oxide layers. After some searching, all I can find is the reaction $\ce{Ti + O2 \to TiO2}$, which I am having no trouble ...
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Equilibrium cell potential question

In an attempt to wrap my head around the basics of electrochemistry I'm working my way through Wesley R. Browne's 'Electrochemistry' primer. With regards to the equilibrium potential of an ...
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1answer
281 views

Why is the peak-to-peak separation of cyclic voltammetry is 57 mV?

I'm studying CV, and I wonder if I can calculate the peak-to-peak separation of CV for a reversible redox system. I found that the separation is 57 mV on my textbook, and my teacher taught me that is ...
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2answers
138 views

For a copper/copper sulfate half reaction, do sulfate anions move to the anode and lose electrons?

In my (high school) textbook, there's an example on finding the charge on 1 mole of electrons, which involves performing the electrolysis of an aqueous copper (II) sulfate using a copper anode and a ...
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1answer
991 views

How exactly does a battery work (specifically Pb/H2SO4/H2SO4/PbO2 lead acid battery)?

Specifically talking about the lead-acid battery, I understand (or think I understand) this much: The anode, in the presence of the electrolyte, $\ce{H2SO4}$ will be oxidised: $$\ce{Pb (s) + SO4^2- (...
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2answers
103 views

How does polarity of a solvent increase conductance of electrolyte?

My textbook says that electrolyte ionize more in polar solvents and greater is the polarity, larger is the conductance. But if polar solvents (lets take water) causes the formation of shells around ...
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Is my understanding of cyclic voltammetry correct? [closed]

So recently I've been roped into doing some CV and I'm trying to wrap my head around the fundamentals of the science behind it (and electrochemistry more generally! Bare in mind I'm very much not an ...
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1answer
40 views

How do you work out whether reduction would occur based on reduction potentials [closed]

I'm having a bit of trouble with standard reduction potentials. Specifically, when you're given a table of half reactions and reduction potentials...is the potential of the reverse reaction (the ...
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1answer
31 views

Reaction in Zinc-Carbon-Ammonium Chloride battery

I made a dry cell battery from zinc (Zn), carbon (C) and ammonium chloride (NH4Cl) which produced a current of 0.4 amps and voltage of 1.1V. However when I could not find the redox reaction that was ...
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1answer
2k views

Are Daniell cells rechargeable (reversible)?

I know that the Daniell cell is a primary cell and the reaction occurs as: $$\ce{Zn -> Zn^{2+} + 2e^-}$$ $$\ce{Cu^{2+} + 2e^- -> Cu}$$ However, I do not know if we can reverse the reaction by ...
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1answer
59 views

Is this galvanic cell representation right?

Question 13. In the galvanic cell: $$\ce{Pt(s) | I2(g) | I-(aq) || Fe^3+(aq) | Fe^2+(aq) | Pt(s)}$$ Representation of anode is incorrect and cell will not work. $[\ce{Fe^3+}] = [\ce{Fe^2+}] = [\ce{I-...
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Writing a electrochemical cell representation in correct way [closed]

The answers to following question seem wrong to me. The books has plainly told correct answer is (3), but it seems incorrect to me. Please help.
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1answer
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How ro interpret the given cell representation? [closed]

I have encountered cell emf having a reactant and product in the subscript. But this is the first timeI have witnessed 3 elements/compounds/ ions. How do i interpret this and what would be the ...
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2answers
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What is the magnitude of the current in an electrolyte? [closed]

if a battery is connected to an electrolytic cell, what is the magnitude of the current in the electrolyte compared to the the magnitude of the current in the wire? This doesn't make sense to me ...
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1answer
2k views

Cell Representation of a galvanic cell:

I know basic cell representations of galvanic cells and can identify the anode/cathode. But here's a weird representation that I encountered and couldn't understand it: $$\ce{Pt | H2(g)}(\pu{1.0 atm})...
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Which will be oxidised between water and Copper?

I have always read that the one having higher discharge potential undergoes the reaction( oxidation or reduction). But In this example why is there also oxidation of water?
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2answers
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Does voltage or current matter most when setting up an efficient water electrolyzer? [closed]

I am setting up a homemade water electrolyzer for producing hydrogen gas, which will solely be used by myself for experimental purposes, and have heard the wattage used has a large part to play in ...
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Calculating Ka using Nernst Equation

I've heard multiple times that the Nernst Equation could be used to calculate K$_a$. How would one calculate the acidity constant, K$_a$, of a specific acid, using the Nernst Equation? The equilibrium ...
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1answer
148 views

Does Intercalation and Deintercalation of Lithium ions occurs in Half Cell?

The important feature of Lithium ion batteries is the ability to intercalate and deintercalate lithium ions in anode and cathode . However when we use half cell, using lithium metal foil as anode, ...
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1answer
290 views

what should be the onset potential using cyclic voltammetry?

I am working for PEM fuel cell cathode material. I am confused regarding the onset potential determination for my catalyst (CV attached, fig 1 is complete CV while fig 2 is its zoom image for clear ...
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3answers
53 views

Activities and molar concentrations

I would be really happy if someone would clarify the term "chemical activity" and its implications for me, and also how it is related to the concept of molar concentration. My textbook fails at ...
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1answer
547 views

Kohlrausch Law and conductivity

Im writing up a lab report at the minute and part of it concerns ions in solution and how they affect conductivity. I've been doing lots of reading and I think ive got the grasp of most of it, but its ...
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1answer
84 views

Current in a Lithium Ion Battery

I am trying to find the current transferred to the anode and cathode of a Lithium Ion Battery at different voltages. I know the temperature (approximately) of the battery, the battery's starting ...
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776 views

Electronegativity

Why is the Electronegativity difference for atoms in bonding uncertain while determining what the compound will be? According to the IB(International Baccalaureate) they say that the ...

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