AQA GCSE Chemistry (8462), Higher tier · Chemical analysis › Identification of common gases
Practise Test for hydrogen. 11 exam-style questions on this subtopic, at up to four difficulty levels, with full mark schemes and a progress tracker. Free, no account needed.
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Name the product of the reaction between hydrogen and oxygen.
water
The squeaky pop happens because hydrogen reacts very quickly with oxygen in the air. Name the product of this reaction.
water
A student adds excess magnesium ribbon to dilute sulfuric acid in a conical flask fitted with a delivery tube, and collects the gas produced over water in an upturned test tube. Name the salt produced in this reaction.
magnesium sulfate
Complete the word equation for the reaction. zinc + hydrochloric acid → .................... + hydrogen
zinc chloride
Sample questions
Written for this site in the style of AQA exam questions. They are not taken from real past papers.
Question 1Easy3 marks
A student added magnesium ribbon to dilute hydrochloric acid in a test tube. A gas was produced.
(a) Give one observation that would show a gas is being produced.[1]
(b) The gas was hydrogen. Describe the test for hydrogen and give the result.[2]
Show the answer and mark scheme
(a)
bubbles / fizzing / effervescence
(b)
(hold a) burning / lit splint at the open end of the test tube
(the hydrogen burns rapidly with a) (squeaky) pop
Question 2Medium4 marks
Hydrogen can react rapidly with oxygen from the air. The reaction makes a squeaky pop.
(a) Name the product of the reaction between hydrogen and oxygen.[1]
(b) Balance the equation for the reaction. ....H2 + ....O2 → ....H2O[1]
(c) A student collected a test tube of an unknown gas and put a glowing splint into it. The splint did not relight. The student concluded that the gas was hydrogen. Explain why the student's conclusion is not valid.[2]
Show the answer and mark scheme
(a)Answer: water
water / water vapour / steam
(b)Answer: 2H2 + O2 → 2H2O
2H2 + O2 → 2H2O
(c)
a glowing splint is the test for oxygen / only shows that the gas is not oxygen
to show the gas is hydrogen, hold a burning splint at the mouth of the tube and listen for a (squeaky) pop
Question 3Hard7 marks
A student electrolyses dilute sulfuric acid using inert electrodes. Gas bubbles are produced at both electrodes.
(a) Predict the gas produced at the negative electrode (cathode). Explain your prediction.[2]
(b) Describe a test the student could use to confirm this gas, and give the expected result.[2]
(c) The student collects the gas from the positive electrode and tests it with a lit splint. There is no pop. The student concludes that the gas is oxygen. Explain why this result alone does not justify the conclusion, and describe the test that would confirm it.[3]
Show the answer and mark scheme
(a)Answer: hydrogen
hydrogen
hydrogen ions are attracted to the negative electrode, where they gain electrons (are reduced) to form hydrogen gas
(b)
collect a sample of the gas from the electrode and hold a lit splint at the mouth of the tube
a squeaky pop is heard
(c)
no pop only shows that the gas is not hydrogen; it does not identify the gas