Edexcel IGCSE Chemistry 4.28 bromine water test
Practise bromine-water questions by comparing alkane and alkene observations, products and reaction conditions in tests.
- Syllabus
- First assessment 2019
- Course
- Chemistry 4CH1
Exam points
- Describe the bromine water test: add bromine water and observe decolourisation.
- Distinguish ethane from ethene using orange bromine water staying orange or turning colourless.
- Compare alkane and alkene bromination by conditions, products and reaction type.
4.28 Bromine-water test question 1
[Maximum number: 2]
This question is about hydrocarbons.
Another homologous series of hydrocarbons is the alkenes.
Alkenes are unsaturated hydrocarbons.
Describe a test to show that a hydrocarbon is unsaturated.
- add bromine water / bromine solution
- bromine water / solution is decolourised or turns from orange to colourless
Accept:
- BrX2(aq)
- add acidified potassium manganate(VII); it is decolourised / turns from purple to colourless
Ignore:
- clear
Reject:
- discoloured
- any incorrect initial colour
Marking guidance:
- If the initial colour of bromine water is given, it must be correct; allow any combination of orange / yellow / brown.
- The observation mark depends on adding bromine water or a near miss.
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