A student makes four different gases in the laboratory.
| Experiment | Reactants | Gas made |
|---|---|---|
| A | magnesium and dilute hydrochloric acid | hydrogen |
| B | calcium carbonate and dilute hydrochloric acid | carbon dioxide |
| C | hydrogen peroxide solution and manganese(IV) oxide | oxygen |
| D | electrolysis of sodium chloride solution | chlorine |
The table shows the tests for the four gases.
| Gas | Test | Result of a positive test |
|---|---|---|
| hydrogen | hold a lighted splint at the mouth of the test tube | ? |
| oxygen | ? | the splint relights |
| carbon dioxide | bubble the gas through limewater | ? |
| chlorine | hold damp blue litmus paper in the gas | ? |
Complete the table.
Chlorine is toxic.
Suggest one safety precaution the student should take when testing for chlorine.
A student says:
"If a lighted splint goes out in a gas, the gas must be carbon dioxide."
Explain why the student is wrong.
Complete the word equation for the reaction in Experiment A.
magnesium + hydrochloric acid → ...... + hydrogen
52 exam-style questions on OCR GCSE Chemistry 4.2 Identifying the products of chemical reactions, covering 4.2.1 Tests to identify gases, 4.2.2 Tests for aqueous ions and flame tests, and 4.2.3 Instrumental methods of analysis. Each one has a worked solution and a mark scheme showing where the marks go.