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OCR F324 - Question

Question 4b)

http://www.ocr.org.uk/Images/131288-question-paper-unit-f324-rings-polymers-and-analysis.pdf


How do they expect you to do that... What is the thought process you went through if you knew how to answer it?

Maybe if you think about it in terms of the alternative oxidation - reduction definitions i.e gain of oxygen and loss of hydrogen?
(edited 10 years ago)
Original post by IShouldBeRevising_
Question 4b)

http://www.ocr.org.uk/Images/131288-question-paper-unit-f324-rings-polymers-and-analysis.pdf


How do they expect you to do that... What is the thought process you went through if you knew how to answer it?

Maybe if you think about it in terms of the alternative oxidation - reduction definitions i.e gain of oxygen and loss of hydrogen?


You should have learned the reactions of organic compounds and know that aldehydes make carboxylic acids when they are oxidised and primary alcohols when they are reduced.
Original post by charco
You should have learned the reactions of organic compounds and know that aldehydes make carboxylic acids when they are oxidised and primary alcohols when they are reduced.


Yeah but a carboxylic acid is not made.... a salt of a carboxylic acid is formed which is not the same thing.
Original post by IShouldBeRevising_
Yeah but a carboxylic acid is not made.... a salt of a carboxylic acid is formed which is not the same thing.


Yes, but if your conditions are strong base (in this case KOH) then you will get a neutralisation and the acid becomes the salt...
Original post by charco
Yes, but if your conditions are strong base (in this case KOH) then you will get a neutralisation and the acid becomes the salt...


Oh yeah that's true... thank you....

I was just wondering I thought aldehydes are only oxidsied in the presence of an oxidising agent, such as acidified dichromate ions, and reduced in the presence of a reducing agent such as NaBH4.

These are the reagents suggested in the course book... but I am confused as to how oxidation and reduction can take place with KOH?
Original post by IShouldBeRevising_
Oh yeah that's true... thank you....

I was just wondering I thought aldehydes are only oxidsied in the presence of an oxidising agent, such as acidified dichromate ions, and reduced in the presence of a reducing agent such as NaBH4.

These are the reagents suggested in the course book... but I am confused as to how oxidation and reduction can take place with KOH?


This is actually a special reaction called the Cannizzaro reaction.

You are not expected to know it, but there is enough information given in the question to answer it ...
Original post by charco
This is actually a special reaction called the Cannizzaro reaction.

You are not expected to know it, but there is enough information given in the question to answer it ...


Ok... so I should of thought the question tells me aldehyde oxidation and reduction... A primary alcohol and a carboxylic acid... but KOH is present the carboxylic acid will react however the alcohol will not.


Thank you for your help...

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