Testing for Anions

Question 1

Anions =

Answer 1

negative ions

Question 2

carbonate ions CO3 2-

Answer 2

if a carbonate reacts with an acid, it produces, a salt, carbon dioxide and water.

thus, we can add dilute acid to a carbonate in a test tube, collect any gas given off, and use the limewater test to confirm that it is a carbonate.

Question 3

sulfate ions SO4 2-

Answer 3

if we add Barium ions to the sample, they’d react with any sulfate ions to form Barium Sulfate - Barium Sulfate is a white precipitate, so if white precipitate forms, this is a positive result.

Question 4

Before we add barium ions to test for sulfate ions:

Answer 4

add dilute HCl to remove any carbonate or sulfide.

Question 5

In what form do we add the Barium ions?

Answer 5

Barium Chloride solution

Question 6

Testing for halide ions:

Answer 6

Step 1: add dilute Nitric acid to remove any carbonate or sulfide.

Step 2: add silver nitrate -> the silver ions react with the halides to form precipitate - the colour of the precipitate depends on the halide though.

Question 7

Ag + Cl -> AgCl

Answer 7

white precipitate

Question 8

Ag + Br -> AgBr

Answer 8

cream precipitate

Question 9

Ag + I -> AgI

Answer 9

yellow precipitate