All Questions
Tagged with acid-base experimental-chemistry
22
questions with no upvoted or accepted answers
7
votes
0
answers
516
views
Does phosphoric acid remove stainless steel electropolished layer?
Electropolished stainless steel has a high corrosion resistance due to the oxide film that is created during electropolishing. The film mainly consist of chromium(III) oxide.
Phosphoric acid is ...
- 2,205
4
votes
0
answers
447
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Why is the experimental pH of vinegar (acetic acid) so much higher than expected?
I bought some sodium hydroxide on Amazon and went about titrating solutions I make with it.
As I'm an amateur chemist at home, I have limited tools. A pad of paper, some 5% acetic acid vinegar, and ...
- 141
3
votes
0
answers
2k
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Lassaigne's test for sulfur
The sodium fusion extract is acidified with acetic acid and lead acetate is added to it. A black precipitate of lead sulphide indicates the presence of sulphur.
What is the need for acidification of ...
- 3,487
2
votes
1
answer
117
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Difference between change of enthalpy of neutralization between copper and manganese carbonate
I was doing a calorimetry experiment to calculate the change in enthalpy during neutralization reactions between metal carbonates and hydrochloric acid. I experimented with 5 metal carbonates: ...
2
votes
0
answers
444
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How to determine the pH of citrate buffer system
I used this table (http://microscopy.berkeley.edu/Resources/instruction/buffers.html) to make a citrate buffer system. The Pka value is 6.4, and I multiplied the solution by ten to make a larger batch....
- 59
2
votes
0
answers
43
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How to Separate Copper Nanowires in an Alumina Membrane
So, in my Chemistry Lab we had an experiment to use Whatman alumina membranes and GaIn eutectic to create Nickel nanowires through electrodeposition. So essentially Nickel wire electrode and alumina ...
- 29
2
votes
0
answers
689
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Deprotection (debenzoylation) of glucose (sacharide) using NaOMe leads to hydrolysis glucose
I have a problem removing the benzoyl groups of my glucose moiety using sodium methylate (standard procedure). Indeed, the benzoyl groups are removed. However, a significant amount of glucose gets ...
- 21
2
votes
0
answers
2k
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Titration curve, how to find equivalence point
If you have a graphed titration curve and have points near the equivalence point like
6.85 pH at 54.60mL titrant added and
8.01 pH at 54.73mL titrant added
is there any good way to find a more ...
- 21
2
votes
1
answer
2k
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Acid-base titration: Unknown base in burette or flask?
While finding the concentration of $\ce{NaOH}$ via titration with $\pu{0.05M}$ Oxalic acid solution (in our lab) we put NaOH in the burette whereas added phenolphthalein to oxalic acid in titration ...
user84548
1
vote
0
answers
36
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Trends in pKb for both acetic acid and water
I am trying to rationalise a result that I have recently measured in the lab. I'm measuring the pKb of different compounds in anhydrous acetic acid, using the procedure outlined in this paper (https://...
- 11
1
vote
0
answers
365
views
Can I use a mechanical pipette to transfer strong acid?
I am an undergraduate student majoring in physics. I am looking for the best method to accurately measure the volume of strong acids like hydrobromic $(w(\ce{HBr(aq)}) = 48\,\%)$ and hydroiodic $(w(\...
- 27
1
vote
0
answers
416
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How useful is thymol blue (acid) as an indicator?
The pH range of thymol blue (acid) is 1.2-2.8.. This pH range seems pretty useless. Generally, the sudden change in pH for SA-SB titration occurs in the range of 4-10; the sudden change in pH for SA-...
- 201
1
vote
0
answers
45
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How do you purify phosphoric acid from cheap commercial (hardware-store) products?
I am looking for idea's on how to purify phosphoric acid for lab use, as the the price for reagent grade V's home-use ended with me buying a product designed as a rust-killer for steel... The ...
- 11
1
vote
0
answers
114
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Is it true that un-dissociated HCl exists in dilute hydrochloric acid?
My book says that the equilibrium constant for $\ce{HCl + H_2O}$ is so high that the reaction goes to completion. But that does not make sense since the existence of an equilibrium constant for this ...
- 333
1
vote
0
answers
153
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How to test acid-base reactions under pressure?
I am trying to test chemical reactions, more specifically reactions between an acid and a base, at different levels of pressure.
I would like to know if there is some kind of equipment I can get that ...
- 111