All Questions
Tagged with inorganic-chemistry electrochemistry
144
questions
3
votes
0
answers
61
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Short-circuiting an electrolytic cell with metal dendrites and observing interesting chaotic 1/f noise
While conducting home experiments on the electrolytic deposition of copper in a micro-gap (2-3 mm), under a microscope (x40) I observed interesting effects of short-circuiting by metal dendrites of ...
- 115
4
votes
1
answer
95
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Why is my Ni or Fe cathode blackening and pores getting blocked during alkaline (6 M KOH) electrolysis?
I am conducting an electrolysis process for hydrogen $(\ce{H2})$ and oxygen $(\ce{O2})$ generation using a $\pu{6 M}$ $\ce{KOH}$ alkaline solution.
During the process, I have observed that my cathode ...
- 41
0
votes
1
answer
53
views
Determining an unknown E° from two similar half ox/redox reactions
Use the oxidation half-cell and reduction half-cell, $\ce{Cr^3+/Cr^2+} = \pu{0.424 V}$ and $\ce{Cr^3+/Cr2O7^2-} = \pu{1.32 V}$, to determine the $E^\circ$ for $\ce{Cr2O7^2-/Cr^2+}$:
a. $\pu{-1.75 V}$
...
-1
votes
1
answer
77
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Electrolyte in Electrolysis of CuSO4 [closed]
I have 2 questions regarding electrolyte used in electrolytic refining of copper:
I was reading metallurgy of copper and I noticed that in electrolytic refining we use acidified aqueous $\ce{CuSO_4}$ ...
- 363
13
votes
3
answers
2k
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Do electrons really hang around the electrode while ions go take a swim?
This answer to this post addresses "what happens if you dip a single zinc electrode into some electrolyte solution." It explains that
However, though the zinc ion can diffuse through the ...
- 22.5k
2
votes
0
answers
92
views
What is the ionic conductivity of the hydroperoxide ion?
Hydrogen peroxide is supposed to dissociate as
$$\ce{H2O2 <=> H+ + HO2-}$$
But I can't find a source for the conductivity, $\lambda$, of the hydroperoxide anion $(\ce{OOH-}$ or $\ce{HO2-})$ on ...
- 129
0
votes
0
answers
100
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In which medium is Potassium Permanganate a better oxidising agent?
I was in chemistry class just now, and my chemistry teacher gave us three reactions:
Reaction 1: $\ce{MnO4^- + e- -> + MnO4^2- (basic medium)}$
Reaction 2: $\ce{MnO4^- + 4H+ + 3e- -> + MnO2 + ...
- 27
2
votes
1
answer
77
views
What is the difference between using an oven or an IR lamp to dry the coatings of fuel cells?
I wondered how the morphology of the catalyst coating for fuel cells changes if it is dried either in a conventional oven (40 °C, 60°C, 80°C) or under an IR lamp.
I am pretty certain that it changes, ...
- 81
5
votes
1
answer
275
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Why does oxidation of gold with oxygen work in cyanide leaching?
Normally gold can't be oxidizes by oxygen, but in the presence of $\ce{CN}^-$ it works.
In general, I have understood that this is due to the fact that complexation $\ce{[Au(CN)_2]^-}$ decreases the ...
- 369
2
votes
1
answer
339
views
Uncertainty for repeated measurements
I am having some trouble calculating the percent uncertainty of obtained cell potential. My cell potentials were 1.788, 1.787, and 1.792 volts with the uncertainty of voltmeter $\pm$ 0.001 volts. Here ...
- 29
5
votes
4
answers
228
views
Deriving reduction potential from redox reactions
From a past USNCO test:
40. What is the standard reduction potential of $\ce{Hg^2+(aq)}$ to $\ce{Hg(l)}$?
\begin{align}
\ce{2 Hg^2+(aq) + 2 e- &-> Hg2^2+(aq)} &\quad E^\circ &= \pu{+0....
3
votes
0
answers
149
views
Why the change of the position of the salt bridge or metal piece leads to different voltage value?
I am doing an experiment where I use salt bridge to create galvanic cell. The goal of my experiment is to find if there is some correlation between the amount of solvent being used and the voltage ...
- 139
0
votes
1
answer
138
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I have been able to make sulfuric acid from alum using a membrane cell. What else other than alum can I use to improve yields
Here is how I was able to make sulfuric acid.
A membrane cell was made by placing a earthen clay pot in a larger vessel.
1.Make concentrated solution of potash alum.
2.Pour alum sol into both sides of ...
- 29
0
votes
0
answers
77
views
Why is there a discrepancy between predicted and nominal voltages of alkaline batteries?
According to Wikipedia, the sum of standard reduction potentials for the half reactions for alkaline battery yield $\pu{1.43 V}:$
$$\begin{align}
\ce{Zn(s) + 2 HO–(aq) &-> ZnO(s) + H2O(l) + 2 e–...
- 19
1
vote
2
answers
120
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How to determine the cell potential of chromium(III) — permanganate cell?
Determine the cell potential of the following cell:
$$\ce{Pt | Cr^3+ (\pu{0.125 M}), Cr2O7^2- (\pu{0.200 M}), H+ (\pu{0.600 M}) || MnO4- (\pu{0.150 M}), Mn^2+ (\pu{0.400 M}), H+ (\pu{0.250 M}) | Pt}$$
...
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