Test for sulfates Flashcards
1
Q
What does this test for?
A
SO₄²⁻ ions
2
Q
Step 1
A
Add dilute hydrochloric acid to test tube of sample
3
Q
Why add dilute hydrochloric acid?
A
To remove unwanted carbonate ions which would produce a precipitate and give a false positive
4
Q
Step 2
A
Add barium chloride drops to sample
5
Q
Why add barium chloride?
A
Because then the barium ions can react with sulfate ions (if a positive result) in solution to form barium sulfate:
BaSO₄
6
Q
Positive result
A
A white precipitate of BaSO₄ is formed which is insoluble in water
