Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Section
The test for unsaturated compounds
19 practice questions
Practice questions
1–10 of 19
Question 1
1 mark · Easy
Answer and see the solution →State the colour change observed when bromine water reacts with ethene.
Question 2
3 marks · Easy
Answer and see the solution →A student tests samples of pentane and pent-1-ene with bromine water.
(a)[1 mark]State what is observed when bromine water is added to pent-1-ene.
(b)[1 mark]State what is observed when bromine water is added to pentane.
(c)[1 mark]Explain why these observations allow you to distinguish between pentane and pent-1-ene.
Question 3
2 marks · Easy
Answer and see the solution →Write the balanced chemical equation for the addition reaction between propene ( ) and bromine ( ). State the name of the organic product formed.
Question 4
2 marks · Easy
Answer and see the solution →A student tests an unknown hydrocarbon with bromine water. The liquid does not decolourise bromine water. Explain what this result tells you about the type of hydrocarbon and give a reason.
Question 5
3 marks · Easy
Answer and see the solution →A student compares the reaction of different alkenes with bromine water. The results are shown in the table.
Alkene tested Observation with bromine water ethene colourless propene colourless but-1-ene colourless (a)[1 mark]Describe the pattern in the results.
(b)[1 mark]State a conclusion about the reaction between alkenes and bromine water.
(c)[1 mark]Suggest what would happen if pent-1-ene was tested with bromine water.
Question 6
1 mark · Easy
Answer and see the solution →What is the chemical test used to distinguish between an alkane and an alkene?
Question 7
3 marks · Easy
Answer and see the solution →Hept-1-ene is reacted with bromine water.
(a)[1 mark]Write the structural formula of the product formed.
(b)[1 mark]Name the type of reaction that takes place.
(c)[1 mark]State the name of the organic product.
Question 8
2 marks · Easy
Answer and see the solution →A sample of an alkene is tested with bromine water. The orange colour remains. Calculate the number of carbon–carbon double bonds present in one molecule of the alkene and explain your answer.
Question 9
2 marks · Normal
Answer and see the solution →State the overall type of reaction that occurs when bromine water reacts with ethene, and give the name of the organic product formed.
Question 10
4 marks · Normal
Answer and see the solution →(a)[1 mark]Describe the result you would see when bromine water is shaken with a liquid alkene.
(b)[1 mark]Describe what you would see if bromine water is shaken with a liquid alkane, under the same conditions.
(c)[2 marks]Explain how you can use this test to distinguish between an alkene and an alkane.