All Questions
12
questions
1
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Are there TLC stains for organo fluor compounds or anorg. fluoride that are useful for selecting the product containing fractions post purification
Are there TLC stains that work with fluoride or with organofluor compounds? I have a fluorinated phosphonic acid that does not stain with conventional means. I did research in many of the known and ...
- 799
0
votes
1
answer
139
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Should I write formula for oxalate or oxalic acid while balancing a redox reaction using the ion-electron method?
Problem:
Balance the following reaction using the ion-electron method:
$$\ce{H2C2O4 + KMnO4 + H2SO4 -> CO2 + MnSO4 + K2SO4 + H2O}$$
My book's solution:
Oxidation half-reaction:
$$\ce{C2O4^2- -> ...
- 201
0
votes
1
answer
217
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Qualitative analysis of the anionic part of a salt using it's soda extract [closed]
While testing for anions using dilute $\ce{H2SO4}$, we prefer using the soda extract for tests rather than the actual salt. But we don’t use it for tests of carbonates, bicarbonates and sulphites. Why ...
- 445
-2
votes
1
answer
41
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Is Cu stable as Cu(H2O)2+ for determination on MP-AES? [closed]
I have an unknown sample of mineral which I need to dissolve in nitric acid. I need to analyze $\ce{Cu}$ from it on MP-AES. Do I need to add $\pu{1ml}$ of $\ce{HCl}$ to stabilize $\ce{Cu}$, or it is ...
- 5
-2
votes
1
answer
745
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How much NaOH I have to add to increase pH?
I'm stuck in solving this problem. I have two solution of $\pu{5 M}$ $\ce{H2SO4}$ that needs two consequential $\mathrm{pH}$ increasing: the first from the natural $\mathrm{pH}$ of $\pu{5 M}$ $\ce{...
1
vote
1
answer
1k
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When disolving a iron pill for titration, why do I use sulfuric acid instead of nitric or hydrochloric acid?
In a titration to decide the iron content of a pill we dissolved the iron in sulfuric acid and then titrated it with cerium(IV) sulfate. But I just wondered what's wrong with using nitric and ...
- 23
0
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2
answers
3k
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Sodium Sulfate vs Sodium Sulfite
I recently took a test and one of the questions was:
Which procedures will allow a student to differentiate between solid sodium sulfate and solid sodium sulfite?
I. Make solutions of each ...
- 2,109
-1
votes
2
answers
5k
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Lab Methods for Determination of Phosphoric Acid Concentration
Dear stack exchange,
For my next lab session we have been tasked to come up with two different methods for determining the concentration of an unknown sample of phosphoric acid.
Design at least ...
- 33
3
votes
1
answer
276
views
Dissolving copper minerals in acid
I have copper minerals in rock that has been pulverized. These copper minerals are pure (native copper), chalcocite, chrysacolla, malachite, tenorite, cuprite and azurite. Does anyone know which acids ...
- 31
6
votes
1
answer
2k
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Why should I acidify twice in the procedure for qualitative analysis of chloride anions?
Separation of the Chloride ($\ce{Cl-}$); Confirmation of Chloride.
Chloride ion forms an insoluble silver compound. Silver chloride is a white solid.
$$\ce{Cl^-(aq) + Ag+(aq) -> AgCl(s)}$$
...
- 3,050
0
votes
1
answer
502
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Possible products from anion analyses [closed]
What are possible products from these two anion analyses?
The nitrite test, reacting diphenylamine with a nitrite:
$$
\ce{(C6H5)2NH + NO2- -> ?}
$$
The sulphite test, reacting potassium ...
- 1,683
2
votes
1
answer
670
views
Can F2/HF be separated using acid/base solutions in series?
I am trying to verify the results of EPA method 26A (http://www.epa.gov/ttnemc01/promgate/m-26a.pdf). The Method claims to be able to separate and quantify a mixed halogen/halide gas stream. Although ...
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