Give a simple test that would allow you to distinguis between the following pairs of anions. Tell what you would do and what you should observe for each anion.
A. CO3^2- and SO4^2-
B. Cl- and SO4-
C. CO3^2- and Cl-
Now, for each cation
A. B^3+ and Ca2+
B. Ca^2+ and Sr+
C. Ca^2+ and NH^4+
Hints: you must supply the details.
A. Add dil HCl and observe bubbles CO2. Add BaCl2 after all of the CO2 has been released.
B. Add BaCl2
C. Acidify the solution, heat to drive off CO2, add AgNO3.
Cations:
A flame test
B. flame test
C. Add concentrated NaOH.
To distinguish between the given pairs of anions and cations, we can use various tests that can provide observable differences. Here's a simple way to distinguish between each pair:
A. CO3^2- and SO4^2-
1. Test for CO3^2-:
Add dilute hydrochloric acid (HCl) to a sample of the unknown substance.
Observation: Bubbles of carbon dioxide gas (CO2) will evolve.
2. Test for SO4^2-:
Add barium chloride (BaCl2) solution to a sample of the unknown substance.
Observation: A white precipitate of barium sulfate (BaSO4) will form.
B. Cl- and SO4^2-
1. Test for Cl-:
Add silver nitrate (AgNO3) solution to a sample of the unknown substance.
Observation: A white precipitate of silver chloride (AgCl) will form.
2. Test for SO4^2-:
Add barium chloride (BaCl2) solution to a sample of the unknown substance.
Observation: A white precipitate of barium sulfate (BaSO4) will form.
C. CO3^2- and Cl-
1. Test for CO3^2-:
Add dilute hydrochloric acid (HCl) to a sample of the unknown substance.
Observation: Bubbles of carbon dioxide gas (CO2) will evolve.
2. Test for Cl-:
Add silver nitrate (AgNO3) solution to a sample of the unknown substance.
Observation: A white precipitate of silver chloride (AgCl) will form.
Now, let's move onto distinguishing between the given pairs of cations:
A. B^3+ and Ca2+
1. Test for B^3+:
Add hydrochloric acid (HCl) to a sample of the unknown substance.
Observation: No specific reaction occurs.
2. Test for Ca2+:
Add ammonium oxalate ((NH4)2C2O4) solution to a sample of the unknown substance.
Observation: A white precipitate of calcium oxalate (CaC2O4) will form.
B. Ca^2+ and Sr^2+
1. Test for Ca^2+:
Add ammonium oxalate ((NH4)2C2O4) solution to a sample of the unknown substance.
Observation: A white precipitate of calcium oxalate (CaC2O4) will form.
2. Test for Sr^2+:
Perform a flame test by heating the unknown substance in a Bunsen burner flame.
Observation: A red flame coloration will be observed.
C. Ca^2+ and NH4^+
1. Test for Ca^2+:
Add ammonium oxalate ((NH4)2C2O4) solution to a sample of the unknown substance.
Observation: A white precipitate of calcium oxalate (CaC2O4) will form.
2. Test for NH4^+:
Add sodium hydroxide (NaOH) solution to a sample of the unknown substance and heat it.
Observation: A pungent smell of ammonia (NH3) will be detected.
By performing these tests and observing the specific reactions, you can identify the different pairs of anions and cations accurately.