Chemical Analysis

Question 1

Test for Carbon dioxide

Answer 1

Bubbling carbon dioxide through an aqueous solution of calcium hydroxide (limewater) causes the solution to turn cloudy.

Question 2

Tests for metal ions

Answer 2

Lithium- crimson 
Sodium- yellow
Potassium- lilac
Calcium- orange/red
Copper- green

Question 3

Test for Halides

Answer 3

To identify a halide ion, add a couple of drops of dilute nitric acid, followed by a couple of drops of silver nitrate solution.
A chloride gives a white precipitate of silver chloride.
A bromide gives a cream precipitate of silver bromide.
An iodide gives a yellow precipitate of silver iodide.

Question 4

Test for carbonates

Answer 4

Put a sample in a test tube and then using a pipette to add a couple of drops of dilute acid. You should then connect the test tube to a test tube of limewater. If carbonate ions are present, carbon dioxide will be released that will turn the limewater cloudy when it bubbles through it.

Question 5

Test for sulphates

Answer 5

Use a dropping pipette to add a couple of drops of dilute hydrochloric acid followed by a couple drops of barium chloride solution to a test tube containing the mystery solution.
If sulphate ions are present, a white precipitate of barium sulfate will form.
Ba2+ +SO42-= BaSO4