How to test for an alcohol

On the OCR A level Chemistry specification this complication would never be taken into account. Anyway I thought it was oxidation of an alcohol where tertiary is a no-reactor. Unless this test does involve oxidating the alcohol to change the colour, but even if this is so, you won't be tested on this complicated scenario. Seriously.

Can you not reduce the 3ry alcohol to a ketone then test for the presence of ketones?

This would also show a positive test with carboxylic acids.

Use the jones oxidation to test for primary and secondary alcohols and the lucas test for secondary and tertiary alcohols.

This would also show a positive test with carboxylic acids.

Use the jones oxidation to test for primary and secondary alcohols and the lucas test for secondary and tertiary alcohols.

The thing is ive done the entire coursework and got my flow chart i just need to see if the compound i have is any form of alcohol so that i can oxidise it if it is

This would also show a positive test with carboxylic acids.

Use the jones oxidation to test for primary and secondary alcohols and the lucas test for secondary and tertiary alcohols.

HAHA i had thought of that but i decided it wasnt "scientifically accurate" and if i die i cant carry on with my experiments to find out what the compound actually is

Yes and the test I have told you is what you need to do.

Acidified potassium dichromate, look for a colour change of orange to green. I've looked it up, and a tertiary alcohol, this test will not work for. However this doesn't matter; they would not overcomplicate things and make you do the dichromate test on a tertiary alcohol, only to be caught out.

What are the lucas and jones tests? I am really interested, but google came up with no results.

I am doing that test later on because i dont necessarily have an alcohol. I could also have a carboxylic acid or an ester so if i oxidise it and there is no colour change i am left with either a tertiary alcohol, an ester or a carboxylic acid and i wont know which

On the upside... if you die it doesn't matter to you what the compound is; nothing does, you're dead.

essentially potassium dichromate oxidation (goes green for 1ry and 2ry alcohols)

lucas test (add lucas reagent (contains ZnCl2)) goes cloudy for 2ry and 3ry alcohols

I knwo after the last thread you probably wanna slap me now but if i do that i can then use litmus paper cant I. (yeah you guessed it) so alcohols arent acidic are they?

Why don't you just look in your book. You have all the information needed to work everything out - there is nothing etra needed - just some common.

Do you really think i havent done that. I got all the other infomation from it but im not sure on this one part. Also, common sense is where you finish your sentences

I am doing that test later on because i dont necessarily have an alcohol. I could also have a carboxylic acid or an ester so if i oxidise it and there is no colour change i am left with either a tertiary alcohol, an ester or a carboxylic acid and i wont know which

You are not exactly required to think outside the box.


If it's tertiary, can't be oxidised. If it's primary or secondary, eliminated to get a geo - isomer for the secondary, and none for the primary. That is just AS stuff.

For the caroxylic acid ? ester ? tertiary?. Well, you put the test for carboxylic acid up before, and someone pointed out how easy it would be to test for the ester. These were simple A2 knowledge.

I'm just saying maybe if you persevered you would have aced this question without help and had amuch firmer grasp of the material.

Your definition of geometric isomers is not the accepted one.
But-1-ene and but-2-ene are not geometric isomers. Geometric isomers are cis- and trans- forms of the same unsaturated molecule. What you have quoted are positional isomers.
Incidentally, you will get geometric isomers of the but-2-ene formed by elimination from butan-2-ol.

In the IB syllabus all of the 1º, 2º, 3º differentiation depends on oxidation. If oxidation occurs all the way to a carboxylic acid its 1º. If oxidation occurs to a ketone its 2º and if there is no oxidation its 3º.

Lucas's test for 1º, 2º, 3º I posted last year:
http://www.thestudentroom.co.uk/showthread.php?p=8415338&highlight=testing+for+alcohols#post8415338

For the but - 2 -ene, cis and trans isomerism is clearly possible from the elimination reaction. This was clear when I said - you can test for geometrical isomers. I clearly stated that there were no geo isomers for but - 1 -ene, but you would need to test for but - 2- ene. Please think before posting.

You can test between a 1ry and 2ry alcohol by adding conc H2SO4 to each. If you have a 2ry alcohol, you will obtain a mixture of 2 geometric isomers. For example, if it was butan - 2 - ol, you would obtain but - 1 - ene and but - 2- ene.