Chemistry 11–12 · Year 12
Dehydration of ethanol to ethene over a hot catalyst, with the gas tested by bromine water (teacher demonstration)
Module 7: Organic Chemistry
Teacher-led demonstration
A teacher carries out this activity as a demonstration. Its materials, steps, variables, misconceptions and sources are not published on the open web, and neither is any result, control or note that states a number or an amount: tutors and administrators read them on the learning platform, with the safety card first. The idea, the hazards and the curriculum references are below.
Open the procedure on the learning platform (tutor or administrator sign-in)
School laboratory, not for home
In a school laboratory, with a teacher supervising, under the school's risk assessment. Not for home.
The idea
Heating ethanol vapour over a solid catalyst removes water and forms an alkene, and the collected gas decolourises bromine water where ethanol vapour does not.
Safety card
Setting: In a school laboratory, with a teacher supervising, under the school's risk assessment. Not for home.
Hazards
- ethanol vapour and ethene are flammable; the tube can ignite at the mouth
- suck-back of cold water into the hot tube can shatter it
- bromine water toxic and corrosive
Controls
At least one of them states a number or an amount, which may be part of the method, so the controls are shown with the method to tutors and administrators on the learning platform.
Note
It states a number or an amount, which may be part of the method, so it is shown with the method to tutors and administrators on the learning platform.
What you should see
Ethene burns with a yellow, slightly smoky flame; the bromine water goes from orange to colourless within seconds of shaking, while bromine water shaken with ethanol stays orange, so the decolourising substance is not ethanol vapour. Water droplets condense in the cooler part of the tube.
Curriculum references
The NSW syllabus outcomes and Australian Curriculum v9 codes this activity supports. They are references, not a verified or complete curriculum alignment.
- Chemistry Stage 6 Syllabus (2017), NESA; the current syllabus, taught in 2026 (codes read from the syllabus document)CH12-14CH11/12-5CH11/12-7
- Chemistry Stage 6 Syllabus (2017), NESA; the current syllabus, taught in 2026 (codes read from the syllabus document); a Working Scientifically outcome not among those the syllabus targets in Module 7, which it allows in any moduleCH11/12-3
- Chemistry 11-12 Syllabus (2025), NESA; implemented from 2028, not yet taughtCH-12-03CH-12WS-03CH-12WS-07
- Australian Curriculum v9No Australian Curriculum v9 code is listed.