Testing For Ions

Question 1

The Carbonate Test

Answer 1

1) Add a strong acid (e.g. dilute nitric acid) to the test sample
2) If CO2 bubbles are produced the sample may be a carbonate
3) If limewater turns cloudy (because of CaCO3), a carbonate is present

Question 2

Observations for the carbonate test

Answer 2

1) CO2 Bubbles are produced

2) calcium carbonate turns limewater cloudy

Question 3

The Sulfate Test

Answer 3

1) Add Barium Nitrate solution, Ba(NO3)2 to a test sample of the unknown substance
2) If you get a white Barium Sulfate precipitate, a sulfate ion is present

Question 4

Order of tests

Answer 4

1) Carbonate
2) Sulfate
3) Halide

Question 5

Why do you do the test in this order?

Answer 5

To prevent false positives

Question 6

NH+ ionic equation

Answer 6

NH4+ (aq) + OH- (aq) —–> NH3 (g) + H2O (l)

Question 7

Halide Test

Answer 7

1) Add nitric acid to the test sample
2) Add dilute silver nitrate
3) A coloured precipitate will form depending on what ion

Question 8

Test for NH4+ ions

Answer 8

1) Add aqueous sodium hydroxide (NaOH) to a boiling tube
2) Heat the tube using a bunsen burner
3) Ammonia gas will be released, turning red litmus paper blue

Question 9

Ammonium test observation

Answer 9

Ammonia gas is produced, turning red litmus paper blue

Question 10

Sulfate Test Ionic equation

Answer 10

Ba^2+ + SO4^2- —–> BaSO4