I posted before about designing a procedure to determine two unknowns (1 solid, 1 solution). The possible solutions were: NaCl, CaCl2, CuSO4, NaOH,Ba(OH)2, HCl, HNO3, or H2O. The reagents given are: NaOH, HCl, AgNO3, Zn metal, Na2SO4, and H2O.
The procedure I've designed so far is:
1) Look at colour, if blue, it is CuSO4
2) Test a bit of unknown with Zn. If there is a reaction it has hydrogen.
3) Add AgNO3, if there is no reaction, it is HCl or KNO3.
4) Add HCl and Na2SO4, if no reaction it is Ba(OH)2.
5) Add HCl and Zn, if no reaction it is NaOH.
6) Add AgNO3, if no reaction it is H2O.
7) Add Na2SO4, if no reaction, it is CaCl2.
8) It is NaCl
Can someone please check over this to see if this would work?
The procedure I've designed so far is:
1) Look at colour, if blue, it is CuSO4. OK
2) Test a bit of unknown with Zn. If there is a reaction it has hydrogen. I don't know what you have in mind but this won't tell you much unless it's HNO3 or HCl and litmus paper might do just as well. How will you know it is hydrogen?
3) Add AgNO3, if there is no reaction, it is HCl or KNO3. AgNO3 reacts with HCl to produce AgCl, an insoluble white ppt.
4) Add HCl and Na2SO4, if no reaction it is Ba(OH)2. Separately or both at the same time? Na2SO4 and Ba(OH)2 produce a white ppt of BaSO4 insoluble in HCl or most anything else
5) Add HCl and Zn, if no reaction it is NaOH. I don't understand this one either.
6) Add AgNO3, if no reaction it is H2O. Why couldn't it be HNO3 or KNO3?
7) Add Na2SO4, if no reaction, it is CaCl2. It could be any of those EXCEPT Ba(OH)2.
8) It is NaCl I don't understand this one unless it's all that's left
Here is a list of the solubility rules.
http://www.chem.vt.edu/RVGS/ACT/notes/solubility_rules.html
balance the following double displacement reaction equations. indicate the precipitate with an (s) Pb(NO3)2 +HCl----->PbCl2 + HNO3.
CaCo3 + HCl---->H2CO3 + CaCl2.
Your procedure seems to have the right idea, but there are a few issues that need to be addressed. Here's a revised version of your procedure along with explanations for each step:
1) Look at the color: This step is fine since CuSO4 is known to have a blue color. However, it's worth noting that color is not always a reliable indicator, so additional tests are needed to confirm.
2) Test with Zn: Testing a bit of the unknown with Zn can help determine if it produces hydrogen gas. If a reaction occurs, it indicates the presence of a compound that can release hydrogen ions, such as an acid. However, it's important to note that not all acids will react with Zn, so this test alone may not give definitive results.
3) Add AgNO3: This step is intended to differentiate between HCl and KNO3. However, AgNO3 reacts with both HCl and KNO3, forming a white precipitate of AgCl. So, the absence of a reaction with AgNO3 doesn't necessarily indicate that the unknown is HCl or KNO3.
4) Add HCl and Na2SO4: This test is aimed at identifying Ba(OH)2. However, adding HCl and Na2SO4 might not be sufficient to confirm the presence of Ba(OH)2. Ba(OH)2 is a strong base and would react with HCl, forming water and a white precipitate of BaCl2. So, if you observe a white precipitate after adding HCl and Na2SO4, it could indicate the presence of Ba(OH)2, but further tests may be needed.
5) Add HCl and Zn: This step is meant to detect NaOH. However, adding HCl and Zn might not conclusively indicate the presence of NaOH. NaOH is a strong base and would react with HCl, forming water and a salt (NaCl). But this reaction might not be readily observable. Therefore, additional tests should be conducted to confirm the presence of NaOH.
6) Add AgNO3: This step is designed to differentiate between H2O and other compounds. However, AgNO3 doesn't react with water, so the absence of a reaction with AgNO3 doesn't necessarily indicate that the unknown is H2O. Additional tests will be needed to confirm.
7) Add Na2SO4: This step is aimed at identifying CaCl2. CaCl2 is soluble in water and, when combined with Na2SO4, would form a white precipitate of CaSO4. So, if you observe a white precipitate after adding Na2SO4, it could indicate the presence of CaCl2, but further tests may be necessary.
8) If none of the previous steps have provided a conclusive result, then it is reasonable to assume that the unknown is NaCl. This assumes that NaCl is the only remaining compound that hasn't been identified through the previous tests.
It's important to note that the proposed procedure is a series of qualitative tests and can provide indications, but not definitive proof of the identity of the unknown substances. To confirm the results, further confirmatory tests or more advanced analytical techniques may be necessary.