3.1.4 - Qualitative Analysis Flashcards
1
Q
How do you tests for carbonate ions?
A
Add dilute HCl, effervescence suggests carbonate. Then bubble through limewater. Turns cloudy indicates CO2, and therefore carbonate.
2
Q
How to test for sulphate ions?
A
Add dilute HCl then add BaCl2 to form white precipitate of BaSO4.
3
Q
Why do we add HCl when testing for sulphate ions?
A
To remove any anions that would otherwise interfere with the results by giving false positives.
4
Q
How to test for Cl- ions?
A
Add AgNO3 = white precipitate. Dissolves in dilute NH3.
5
Q
How to test for Br- ions?
A
Add AgNO3 = cream precipitate, dissolves in concentrated NH3.
6
Q
How to test for I- ions?
A
Add AgNO3 = yellow precipitate, doesn’t dissolve in concentrated NH3.
