Tests for Anions

Describe the test for Carbonates (CO₃^2- ions)

• Dilute acid added with pipette, connected with a tube to a test tube of limewater. Positive test if limewater goes cloudy.

• Add drops of dilute hydrochloric acid. Add drops of barium chloride solution. Positive test if white precipitate forms.

• Add drops of dilute nitric acid. Add drops of silver nitrate solution. Different precipitates formed for each Anion.

• Flame test.

• Add sodium hydroxide solution. Different precipitates formed with each Cation.

Describe the test for Sulfates (SO₄^2- ions)

• Dilute acid added with pipette, connected with a tube to a test tube of limewater. Positive test if limewater goes cloudy.

• Add drops of dilute hydrochloric acid. Add drops of barium chloride solution. Positive test if white precipitate forms.

• Add drops of dilute nitric acid. Add drops of silver nitrate solution. Different precipitates formed for each Anion.

• Flame test.

• Add sodium hydroxide solution. Different precipitates formed with each Cation.

Describe the test for Halides (Cl^-, Br^-, I^-)

• Dilute acid added with pipette, connected with a tube to a test tube of limewater. Positive test if limewater goes cloudy.

• Add drops of dilute hydrochloric acid. Add drops of barium chloride solution. Positive test if white precipitate forms.

• Add drops of dilute nitric acid. Add drops of silver nitrate solution. Different precipitates formed for each Anion.

• Flame test.

• Add sodium hydroxide solution. Different precipitates formed with each Cation.

Exam style question: An unknown solution is tested with a few drops of hydrochloric acid and then barium chloride solution. What precipitate will form for a positive test? [1 mark]

• Barium Sulphate (White)

• Barium Chloride (White)

• Barium Sulphate (Yellow)

• Barium Chloride (Yellow)

Tests for Anions: Test for Halide forms a white precipitate, What is this?

• Iodine has been tested, silver iodide.

• Bromine has been tested, silver bromide.

• Chlorine has been tested, silver chloride.

Tests for Anions: Test for Halide forms a cream precipitate, What is this?

• Iodine has been tested, silver iodide.

• Bromine has been tested, silver bromide.

• Chlorine has been tested, silver chloride.

Tests for Anions: Test for Halide forms a yellow precipitate, What is this?

• Iodine has been tested, silver iodide.

• Bromine has been tested, silver bromide.

• Chlorine has been tested, silver chloride.

Exam style question: A fuel is a mixture of liquids that has been designed as a useful product. What name is given to this type of mixture? [1 mark]

• Catalyst

• Formulation

• Polymer

• Solvent

Exam style question: What is the test for chlorine gas? [1 mark]

• A glowing splint relights

• A lighted splint gives a pop

• Damp blue litmus paper turns white

• Limewater turns milky

Exam style question: A solid was tested using a flame test and it gave a green flame. It was then dissolved in some distilled water and gave a white precipitate with barium chloride. What was the compound? [1 mark]

• Calcium chloride

• Copper sulfate

• Calcium sulfate

• Copper chloride