Prep Of Ethene Flashcards
Ways of avoiding suck-back
Loosen stopper, do not remove heat source with delivery tube in water.
Ways of avoiding a fire
Keep ethene and flame separate, turn off gas at end to avoid igniting ethene.
KMnO4 colour change
Purple/Lilac -> Colourless
Bromine water colour change
Brown -> Colourless
Bromine Organic Reaction Type
Addition Reaction
Organic Product between Ethene and Bromine
1,2 - dibromoethane
Catalyst - what it looks like at beginning of preparation
Aluminium Oxide - white powder
Why is there a risk of glassware shattering?
How can this be minimised?
Suck-back / cold water enters hot test tube
Loosen stopper / remove delivery tube before removing heat
Safety Precautions + Explain
Remove delivery tube from water before removing heat - avoid suck-back
Keep ethene away from flame - avoid fire
Ethene + Ethyne combustion tests (flame) - compare
Ethene has a clean flame
Ethyne has a sooty/smoky flame
Balanced equation for the complete combustion of ethene in oxygen
C2H4 + 3O2 —> 2CO2 + 2H2O
Reagent used to test for Unsaturation
Bromine Water
KMnO4
When is suck-back most likely to occur?
When heat is removed at the end
Consequence of suck-back occurring
Cold water goes into hot test tube - glass breaks
Balanced equation for the preparation of ethene from ethanol
What type of reaction?
C2H5OH -> C2H4 + H2O
Elimination reaction
