Question

QUESTIONS Answer the following questions in the data section of your lab report: 1. Use the experience you gained from doing the experiment to answer the following: A student tested an unknown mixture that might contain any of the ions tested in this ex- periment and made the following observations: a. On the addition of 6M HCI, the solution remained colorless and no bubbles were observed. b. When 0.1M BaCl2 was added to the acidified unknown, a white precipitate was formed. c. When 0.1M AgNO, was added to the unknown, a white precipitate was formed. d. When 1M Na2C204 was added, a white precipitate formed. On the basis of the test results, which ions are likely present in the unknown? 2. Why is it more difficult to identify all the ions in a mixture than to identify the cation and anion in a binary ionic compound? For Your Lab Report Discussion: As part of your introduction, explain the following terms: ions; qualitative and quantitative analysis. Using at least one example, explain how qualitative analysis is used in industry, environmental regulation, etc. Summarize the types of reactions and observations of the known ions and explain how you iden- tified the unknown ions. Remember to finish your discussion with errors and precautions. You can also identify an error and then describe the precaution taken to minimize it OR discuss errors and precautions in separate paragraphs.

Answer 1

1.

Test	Observation	Conclusion	Reason for Conclusion
(a) addition of 6M HCl	The solution remained colorless and no bubbles formed.	Ag+ and CO32- is not present	If Ag+ was present a white ppt of AgCl would have formed. And CO32- would form bubbles of CO2 in the acidic medium.
(b) addition of 0.1M BaCl2	White ppt	SO4 2- is likely present.	White ppt is due to BaSO4 formation.
(c) addition of 0.1M AgNO3	White ppt	Cl- is likely present.	White ppt is due to AgCl formation.
(d) addition of 0.1M Na2C2O4	White ppt	Ca2+ is likely present.	White ppt is due to CaC2O4 formation.