Qualitative Analysis Homework - Inference from Q Mixture

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Discussion Overview

The discussion revolves around a qualitative analysis homework problem involving a mixture of two inorganic salts. Participants analyze the results of tests conducted on the filtrate and residue to infer the presence of specific ions based on the lack of visible reactions with various reagents.

Discussion Character

  • Homework-related
  • Debate/contested
  • Exploratory

Main Points Raised

  • One participant suggests that the absence of a visible reaction when adding dilute HCl and BaCl2 indicates that sulfate ions (SO42-) are not present.
  • Another participant questions whether the inference is indeed that there are no sulfate ions, leading to a correction regarding a typo in the original post.
  • There is a discussion about the second part of the question, where the lack of reaction with dilute HNO3, AgNO3, and excess NH3 is analyzed, with one participant proposing that chloride ions (Cl-) are absent.
  • Another participant raises the possibility of ammonia being present, which is met with skepticism.
  • One participant posits that the cations present do not precipitate with chloride ions and suggests exploring which ions do not precipitate with silver ions, suspecting the presence of chlorate ions that can form soluble salts with both barium and silver.
  • There is a request for clarification on which test is being referred to regarding the presence of chlorate ions, indicating some confusion about the tests conducted.
  • A participant notes that the question may be incomplete, as it does not provide enough information to accurately predict the other anion and the two cations involved.

Areas of Agreement / Disagreement

Participants express differing views on the inferences drawn from the lack of reactions in the tests. There is no consensus on the presence of specific ions, and the discussion remains unresolved regarding the implications of the test results.

Contextual Notes

The discussion highlights limitations in the information provided, particularly regarding the residue and the completeness of the question, which affects the ability to draw definitive conclusions about the ions present.

chikis
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Homework Statement


Suppose you have Q as a mixure of two inorganic salts. The mixture was dissolved in water and filtered.
Test were carried out on both the filtrate and residue.
(1)When a portion of the filtrate was poured into dilute HCL + BaCL2(aq), there was no visible reaction. What would be the inference?

(2) When portion of filtrate was poured into dilute HNO3 + AgNO3(aq) + excess dilute. NH3(aq), there was no visible reaction. What would be the inference?

Homework Equations





The Attempt at a Solution


.Suppose there was white precipate insoluble in excess of dilute HCl+BaCl2(aq), I would have suggested that SO42- ion is present but in this case, there is nothing like that, so what would the inference be?


The same apply to (2). Suppose, there was a white precipitate soluble in excess as the portion of filtrate was added to dilute HNO3+ AgNO3(aq). NH3(aq) then I would have suggested that Cl- ion but there was not reaction.
 
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chikis said:
I would have suggested that SO4- ion is present but in this case, there is nothing like that, so what would the inference be?

That there is no SO42-?
 
Borek said:
That there is no SO42-?

Sorry that is a typo. I actually wanted to write SO42-
 
And I answered assuming it was a typo.
 
Borek said:
And I answered assuming it was a typo.

The specific question have not been answered. You only corrected the typo error that I made. Thank you for that anyway.
 
You didn't get it. Lack of any reaction suggests the inference is "no sulfates present in the solution".
 
Borek said:
You didn't get it. Lack of any reaction suggests the inference is "no sulfates present in the solution".

What about the second part of the question,
When portion of filtrate was poured into dilute HNO3 + AgNO3(aq) + excess dilute. NH3(aq), there was no visible reaction. What would be the inference?
 
chikis said:
What about the second part of the question[/b]

What about you trying to analyze the situation and come to some conclusions?
 
Borek said:
What about you trying to analyze the situation and come to some conclusions?

Then I take that Cl- is absent.
 
  • #10
What about ammonia presence?
 
  • #11
Borek said:
What about ammonia presence?

No I don't think so!
 
  • #12
So what is our final conclusion?
 
  • #13
As far as I can see, the cations present in the salts given do not precipitate with Cl-. Can you find out which ions do not precipitate with Cl-? And the anions do not precipitate with silver ion.

Silver and Barium have very few soluble salts. Try to figure out them and you may get your answer.

I suspect the presence of Chlorate ions, which can form soluble salts with both Barium and Silver.
 
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  • #14
AGNuke said:
As far as I can see, the cations present in the salts given do not precipitate with Cl-. Can you find out which ions do not precipitate with Cl-? And the anions do not precipitate with silver ion.

Silver and Barium have very few soluble salts. Try to figure out them and you may get your answer.

I suspect the presence of Chlorate ions, which can form soluble salts with both Barium and Silver.

Please which of the test are you referring to?

Is it the one:
(1)When a portion of the filtrate was poured into dilute HCL + BaCL2(aq), there was no visible reaction. What would be the inference??

OR

Is it the one:
(2) When portion of filtrate was poured into dilute HNO3 + AgNO3(aq) + excess dilute. NH3(aq), there was no visible reaction. What would be the inference?
?
 
  • #15
Both. When our salt is added to HCl + BaCl2, the salt's anion will form "soluble" salt with Barium. When our salt is added to HNO3 + AgNO3 + excess NH3, the salt's anion will form "soluble" salt with Silver as well.

Then I checked the solubility chart - The only anion making soluble salt with both Barium and Silver was Chlorate.

There's a line written in the question - "Test were carried out on both the filtrate and residue.". Care to elaborate what's residue. From the looks of it, the question is incomplete, since it is impossible to accurately predict the other anion and the two cations.
 
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