Okay, the exam is in 2days as you might know, and I am confused about something...
Questions that ask for reagents or chemicals to break or catalyse reactions.
HOW do I distinguish between when I should use
HCL or H2SO4?
& then, how the **** do I know which concentration to use??? Dilute. moderately concentrated or concentrated???
This is completely puzzling me...
Any help will be highly appreciated. Cheers!
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- Thread Starter
- 25-01-2010 20:17
- Thread Starter
- 25-01-2010 20:35
I love you guys so much
- 26-01-2010 10:42
I'm stuck on the same thing. Here's what I know so far from just reading the revision guide like crazy*:
1) Halogen alkanes react with ammonia to form amines using Ethanol and Reflux
2) Alkenes to alcohols need H2SO4 (idk about concentration) and Reflux
3) Dehydraring alchols needs AL203 and heat
4) Primary alcohol to Aldehyde needs heat and acidified potassium dichromate (VI) and sulphuric acid and distillation apparatus
5) Primary alchol to carboxylic acid needs reflux and excess acidified potassium dicrhomate (VI) solution vigourously oxidise
6) In Esterfication you need concentrated HCl and reflux
7) In ester hydrolysis you need diltue alkali like NaOH and reflux
And that's all I know so far. Anyone else want to give it a shot?
Hope that helped and good luck in the exam!
me = prepared for doom :s
* not really crazy. If I was then I wouldn't be reading it, I'm be tearing the pages out and throwing the out of the Empire State building.
- 26-01-2010 11:59
Secondary amide hydrolysis: Heat under reflux with moderately conc HCl or moderately conc NaOH.
Ester formation from alcohol and carboxylic acid: Heat under reflux with conc sulfuric acid.
Ester hydrolysis: Heat under reflux with dilute sulfuric acid, or heat under reflux with dilute NaOH.
They're anal about it, but the mark schemes seem to like the above conditions.
- 26-01-2010 12:01
Reflux is amazing.
It's pretty much always the answer!!! ^^