Questions tagged [electrolysis]

For questions about the chemical concepts of electrolysis.

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390 views

Forming hydrogen sulfide from electrolysis of sodium thiosulfate

So I was doing electrolysis on two silver electrodes and sodium thiosulfate. Some observations The voltage drops extremely fast from 2 V to less than 1 V in 15 minutes, possibly because of the ...
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2answers
1k views

What pressure is created by the electrolysis of water?

I am interested to know what is a reasonable maximum working pressure I could expect against the evolution of oxygen and hydrogen when electrolysing a typical water electrolyte. My aim is to make ...
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922 views

Why isn't mercury electrode used to produce commercial element sodium?

I know that while electrolysing a solution of brine, if we use mercury cathode, we get sodium amalgam instead of having hydrogen gas liberated. Even the Castner-Kellner process uses this to produce ...
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1answer
521 views

Heat energy vs. electrical energy in a galvanic cell or in an electrochemical reaction

How can someone determine heat energy released during an electrochemical reaction? Let's assume a simple galvanic cell at standard environment: $$\ce{Zn(s) -> Zn^2+(aq) || Cu^2+(aq) -> Cu(s)}...
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1answer
201 views

Calculating the E of a galvanic cell

So, I have $\ce{Cr2O7^2-(aq) + 14 H+(aq) + 6 I-(aq) -> 2 Cr^3+(aq) + 3 I2(s) + 7 H2O(l)}$ and I know the concentrations to be like so: $\ce{[Cr2O7^2-]}= 1.6\ \mathrm M$ $\ce{[H+]}= 2\ \mathrm M$ ...
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101 views

Alkaline Water Electrolysis with RbOH

In industry, it appears the alkaline water electrolysis is largely done with solutions of NaOH or KOH - presumably due to low cost. I presume that alkaline water electrolysis is possible under RbOH, ...
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1answer
22k views

Electrolysis of AgNo3 [closed]

I have a solution of $\ce{AgNO_3}$ (is diluted with water). I electrolyse it. What products from at anode and cathode.
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828 views

Silver Nitrate Electrolysis

i have a solution of silver nitrate at 1M. the aim of my experiment is to determine in 40 mins, how much Ag will be deposited. Should i use copper or graphite electrodes.
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3k views

Can redox reactions be reversed?

Suppose I did this reaction by dipping a $\ce{Zn}$ rod in $\ce{CuSO_4}$ solution. $\ce {CuSO4 + Zn -> ZnSO4 + Cu}$ Is there a way to reverse this reaction to $\ce{Cu + ZnSO4 -> Zn + CuSO_4}$? ...
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1answer
178 views

What can be a harmless electrolytic additive for water for creating an oxy-hydrogen flame?

I was thinking of preparing a tiny oxy-hydrogen flame for soldering. I am going to use 6V DC and aluminum sheet as the electrode for this. Now, I have to add some electrolyte to water, that can be a ...
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1answer
361 views

Why don't all electrodes produce the same results in the electrolysis of potassium iodide?

While in lab, I accidentally used two paper clips while trying to electrolyze potassium iodide and all I saw was was phenolphthalein turning pink at the cathode and no brown at the anode. I asked my ...
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1answer
213 views

Storing oxygen generated via water electrolysis

I want to create a somewhat pure oxygen gas from electrolyzing water and using sodium bicarbonate as an electrolyte. How can I harvest the oxygen once it is released from the water, and store it in a ...
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2answers
3k views

How to apply Faraday's law to calculate the charge of metal ions?

Electrolysis of a molten ionic compound with a current of $\pu{0.50 A}$ for $\pu{30 min}$ yielded $\pu{0.700 g}$ of a metallic element at the cathode. If the element has a relative atomic mass of $150....
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85 views

chemical reaction that causes electrolysis of salt water without adding electric current

I am producing hydrogen using house hold items in a capacitor like arrangement in salt water. I assume this is chemical electrolysis. The apparatus produces gas for many weeks that burns orange. Its ...
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1answer
675 views

Electrolysis of water in 0.1 M hydrochloric acid

For water electrolysis in acidic media ($\ce{TiO2}$ anode and $\ce{Pt}$ cathode) the half reactions for water splitting and $\ce{O2/H2}$ evolution are as follows: Anode: $\ce{H2O + 4 H+ -> 4 H+ + ...
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689 views

Electrolysis of water - why not pure water?

In the electrolysis of water, $\ce{H2O}$ molecules are being reduced at the cathode (forming $\ce{H2}$ and $\ce{OH-}$) and oxidized at the anode (forming $\ce{O2}$ and $\ce{H_3O+}$). It is said that: ...
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484 views

Why do we do electrolysis and electroplating using warm electrolyte?

This is a pretty basic question, and I know it has something to do with conductivity, but I'm not quite sure how they are related.
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Can “Common Ion Effect” suppress the dissociation of water molecules in acidulated water?

$$\begin{align} \ce{H2O &<=> H+ + OH-} \\ K &= \frac{[\ce{H+}][\ce{OH-}]}{[\ce{H2O}]} \\ \ce{H2SO4 &<=> 2H+ + SO4^2-} \end{align}$$ In acidulated water water dissociates into ...
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690 views

Differences between galvanic cells and Li-ion?

There are clearly some differences between the classical galvanic cell and the Li-ion batteries, but if one looks at the schematics, they looks a bit similar. Please see below: a) The galvanic cell: ...
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152 views

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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1answer
280 views

What does it mean “A oxidizes on B”

I have just managed to understand the difference between oxidation and reduction. So basically if A oxidises B, then B loses electrons, right? But what does this formulation mean: "A is oxidized on B"?...
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2answers
8k views

Effect of pH on electrolysis

I understand (more or less) that acidification of water helps in the dissociation of water into ions. Acids easily dissociate into ions in aqueous solution. So, accordingly, the hydrogen from the acid ...
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1answer
102 views

Why a low conductance ion such as lithium is used in batteries?

Lithium ions have a relatively low conductance (Wikipedia) so why are they used in batteries, and not sodium, potassium, etc.?
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1answer
290 views

Faraday law in electrochemistry?

Passing electricity through dilute solution of H2SO4 for a certain time period of time liberates 168 ml of gases at stp. The quantity of electric ity used is ? I used the formula W/E = IT/96500 here ...
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0answers
50 views

Magnetically separating H2 and O2 in a volume of gas [duplicate]

I'm using a method of electrolysis where the anode and cathode are in close proximity (~0.7mm) and therefore the separate collection of H2 from the cathode is very difficult. Since O2 is paramagnetic ...
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1answer
494 views

High voltage AC water electrolysis not working

I was trying to use a $500~\mathrm V$ AC power supply to split water, but nothing happened. I tested everything with a $9~\mathrm V$ battery, and it all worked fine. Why did it not work with the ...
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1answer
280 views

Electrolysis of Anhydrous Sodium Hypochlorite

Considering liquid anhydrous sodium hypochlorite: $$\ce{NaClO (l)}$$ Assuming the ions are free, What would be produced if this were electrolysed? As I've found lots of information for it's ...
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1answer
550 views

Brown particles in electrolysis of brine [duplicate]

This is not a duplicate... pls read the whole question.... I am attempting electrolysis of brine (tap water + table salt). I am using HB pencil lead (graphite) as my two electrodes. I am using 12 ...
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3answers
812 views

In my homemade electrolysis setup, only the negative end bubbles?

I've created an electrolysis setup by connecting a $6~\mathrm{V}$ battery to a cup filled with saline water via pencils; I am confused as to why only the negative pencil bubbles though. After running ...
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1answer
1k views

Obtaining calcium

I have an issue with a way of extracting calcium from a muscle tissue (from a steak, to be exact). I would like to calculate the concentration/amount of calcium stored in a piece of the muscle, yet I ...
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1answer
37 views

Why can't electrolysis utilize specific ions for reduction/oxidation

In the electrolysis of water, reduction half equation is $$\ce{2H2O + 2e- -> H2 + 2OH-}$$ with a standard $E$ value of $-0.83\ \mathrm V$. If $\ce{H+}$ is present in water, why can $$\ce{2H+ + 2e- ...
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2k views

Electrolysing vinegar

Yesterday I made a mixture of vinegar and salt and then electrolyzed it. I was just wondering if anyone could tell me what the process created, it would be greatly appreciated.
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684 views

Electrolysis of water with aluminum at the negative pole

I am doing electrolysis of water to collect the hydrogen and I'm running into a problem: on the positive side I'm using graphite from a pencil (I cannot use any other material because it corrodes too ...
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1answer
799 views

How do electrolytes allow electrolysis to occur?

From what I know, when two electrodes are places in a electrolyte (say $\ce{H2SO4}$, which decomposes into $\ce{H}^{+}$ and $\ce{SO4}^{2-}$ in aqueous solution), the negative ion is attracted to the ...
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2answers
150 views

Tried charging a penny/dime battery. Yellow goo bubbled. What did I create?

When I was a young child, I applied 9 volts across an electric cell I made using a penny, a dime, and a salted piece of paper napkin wet with saliva. Immediately, an unknown mustard-yellow liquid ...
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1answer
79 views

Flood Control - electrolysis - limit to rate of conversion?

Flood control - is it possible to use electrolysis to remove flood waters by converting water into oxygen and hydrogan gas? Is there a limit to the amount of water that can be converted at a time? ...
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3answers
8k views

Why does aqueous NaCl conduct electricity?

Could someone please explain why an aqueous solution of NaCl conducts electricity? I've Googled this up but couldn't get a satisfactory answer. This has an answer on Physics.SE but that's too ...
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326 views

Concentration of electrolyte in rust removal

I will be attempting rust removal from a steel gas tank of about 5 liters by means of electrolysis, with steel wire acting as the anode. For the electrolyte I've been advised to dissolve $\ce{Na2CO3}...
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1answer
161 views

Change of potential difference during electrolysis while adding salt

I was conducting a simple experiment at home on electrolysis. Obviously, when you build a circuit with a 9V battery, a lamp, and put two electrodes in water you measure a potential difference of ~9V ...
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2answers
777 views

How does an anode metal come into solution if it cannot react with an electrolyte?

From what I understand, an anode material is chosen so that it does not react with the anode electrolyte solution. I was just wondering, then, that when you have a galvanic cell which has a Mg metal ...
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3k views

Production of hexavalent chromium during electrolysis using a stainless steel as the cathode

I want to do rust removal by electrolysis (sodium carbonate, water solution) Can I use a stainless steel basket as a cathode or will it produce hexavalent chromium ? I know if I use stainless steel ...
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1answer
237 views

Calculating the energy used during electrolysis of NaCl

Suppose we are getting the necessary $\ce{Na}$ for $\ce{HCl}$ out of $\ce{NaCl}$. We need to end up with $V = 100~\mathrm{m^3}$ of $\ce{HCl}$ at standard conditions. Assuming that $\ce{HCl}$ is an ...
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1answer
36 views

Calculating time needed to coat an object using the process of electrolysis

Suppose we have an object with a surface area of $S=1.5~\mathrm{dm^2}$, and we need to coat it with hard chrome. The thickness of the coat should be $d=80~\mathrm{\mu m}$. The mixture used for coating ...
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129 views

NaCl water electrolysis without membrane, how measure the free chlorine concentration?

I'm trying to made electrolysis using water and NaCl. I need at the end a concentration of 2 g/l. How can I measure the free/active chlorine? Do you know a way to "measure" the chlorine during the ...
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67 views

How does one optimize the molar concentration of electrolyte in terms of the rate of electrolysis?

There are many textbooks/recipes for various electrolyte solutions in the electrolysis of water. I know there is a minimum voltage to kick off electrolysis, and I'm supposing a minimum concentration ...
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442 views

Platinum Electrodes

In industry, numerous companies state that they use platinum electrodes for the purpose of electrolysis. My question is: are these electrodes pure platinum or could they also be, for example, another ...
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249 views

Silver electroplating

In most of silver electroplating (or electrorefining) methods, it is mentioned that silver anode is oxidized in aqueous solution of silver nitrate, and that silver is deposited at the cathode (...
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956 views

Calculating Electrode Potential for Electrolytic Cell at Non-Standard States

Recently, I came across an interesting question that left me rather baffled. I was asked to calculate the minimum voltage required for the electrolysis of 1.0 M of NaCl in neutral solution using the ...
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1answer
1k views

Ratio of energy required for electrolysis vs creating water

I had an idea a while back for a machine that would be totally green. Powered by a Hydrogen Fuel Cell. A big question came up: Where do I get the Hydrogen? I assumed that I could just electrolysis of ...
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2answers
4k views

Why does the concentration of hydrogen ions increase in the electrolysis of dilute sulphuric acid?

In the electrolysis of dilute sulphuric acid, I'm given these two half-equations: anode: 4OH-(aq) -> 2H2O(l) + O2(g) + 4e- cathode: 4H+(aq) + 4e- -> 2H2(g) Why does the concentration of hydrogen ...