Organic chemistry question URGENT PLS HELP

Hi, so I came across a question which is:
Explain how you could use an alternative reagent to do a chemical test that would allow you to distinguish between hexene and propanoic acid.

At first I thought to use potassium permanganate which is purple, thinking it would turn both the propanoic acid and hexane brown. But I found out it only turns the hexane brown, and propanoic acid stays purple. Why is this?
I just assumed this permanganate would effect them both the same as they are both becoming oxidised!

Hi Charlotte.
The usual reagent would be Br2 which would quickly lose its orange colour with the hexene (because of the double bond) but not react ( except very slowly if UV light is present) with the propanoic acid. Note that although the acid does have a double bond, it is C=O, not the required C=C of an alkene.
You are correct that potassium permanganate can be used as the alternative reagent because it can oxidise the hexene to form a diol and in the process will lose its purple colour. In contrast the acid will not react (and the purple colour remains) as carboxylic acids cannot be oxidised. You may remember that these acids can be formed by oxidation of a primary alcohol and cannot be oxidised anymore.
Hope that helps.

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I don’t know how to make a new discussion so am asking my question by reply to this question.

Are alkene and alcohol insoluble after 4 carbon bonds?

All hydrocarbons (which includes alkanes AND alkenes) are insoluble regardless of how many carbon atoms it contain.
Because of the presence of the very polar OH group in alcohols, the short chain alcohols are extremely soluble. For example ethanol can dissolve in water in any proportion from 0 to 100%. But as the chain length increases the molecule becomes less polar overall as the non-polar hydrocarbon chain outweighs the effect of the polar -OH group. So there is a general trend for alcohols (or indeed any other organic family such as amines or carboxylic acids) to become less soluble as the carbon chain length increases. For alcohols, once the carbon chain is longer than 4 carbon atoms it is essentially considered insoluble in water (and would form a separate layer on top of the water as it is less dense)

How does the marking work for structure and bonding because for E7 most of the times 2E required but let’s say I get 1E does that become M6 because for M6 3M required so if I get 1E does that get me M6 or do I need M’s as well.

It varies from standard to standard depending on whether it is top down or bottom up marking. But if you only answered 1 part of say a 5 part question and if you got it correct at Ex standard would you expect to get an E7 despite not having attempted 4 out of 5 parts?