Anions Flashcards
what are anions?
negatively charged ions.
what does hydrochloric acid help detect?
carbonates
Describe a test for carbonates
Add DILUTE HYDROCHLORIC ACID to your sample. If CARBONATES are present then CARBON DIOXIDE will be released. You can test for carbon dioxide using LIMEWATER.
what is the equation for carbonates and hydrochloric acid?
carbonate + acid > carbon dioxied + water
CO3(2-) + 2H+ > CO2 + H20
test for sulfates using what?
barium chloride
what do sulfate ions produce?
A white precipitate
Describe a test for sulfate ions
Add DILUTE HYDROCHLORIC ACID followed by BARIUM CHLORIDE solution (BaCl2). A white precipiate of BARIUM SULFATE means the original compond was a sulfate.
What is the hydrochloric acid used for in the sulfate test?
To get rid of any traces of carbonate or sulfite ions before you do the test because they would confuse results.
The equation for barium chloride and sulfate test.
Ba2+(aq) + SO42- (aq) > BaSO4(s)
What three halides do we need to know the tests for?
Cl-, Br-, I-
Chlorine, bromine and iodine.
Describe the test for the three halides.
To test for chloride, bromide or iodide ions, add DILUTE NITRIC ACID (HNO3) followed by SILVER NITRATE solution. (AgNO3)
what colour is the precipitate of silver chloride?
white
what colour is the precipitate of silver bromide?
cream
what colour is the precipitate of silver iodide?
yellow
equation for chloride ion test
Ag+(aq) + Cl- (aq) > AgCl(s)
