Chemistry question help please

Hi, please could I have some help on this question, I’m unsure why I’m wrong because I thought ketone will be reduced to a secondary alcohol but in the markscheme it just had two hydrogens rather than an OH?
Question: https://ibb.co/chxpJKx4
Thanks!

Reply 1

Skjfnvkkgj

4

For a ketone to become a secondary alcohol you need to use potassium dichromate, reducing it just adds hydrogens.

Reply 2

anonymous56754

OP

11

Original post by Skjfnvkkgj

For a ketone to become a secondary alcohol you need to use potassium dichromate, reducing it just adds hydrogens.

No I think LiAlH4 is a reducing agent bu potassium dichromate is an oxidising agent which is used to convert a secondary alcohol to ketone

Reply 3

Skjfnvkkgj

4

Oh my bad I completely messed that up lolll. I blame year 13 mocks but yeah you're right. Maybe show the question to a teacher? Or I could show mine if you want.

Reply 4

anonymous56754

OP

11

Original post by Skjfnvkkgj

Oh my bad I completely messed that up lolll. I blame year 13 mocks but yeah you're right. Maybe show the question to a teacher? Or I could show mine if you want.

No worries lol I just had my mocks too, I’ll show my teacher and let u know what it is.

Reply 5

TypicalNerd

18

Original post by anonymous56754

No I think LiAlH4 is a reducing agent bu potassium dichromate is an oxidising agent which is used to convert a secondary alcohol to ketone

It is - in fact, it’s a very strong reducing agent at that. When used to reduce an amide, it will always form an amine. So basically replace the hydroxyl with a hydrogen and you have the right product

(edited 2 months ago)

Reply 6

TypicalNerd

18

Original post by anonymous56754

Hi, please could I have some help on this question, I’m unsure why I’m wrong because I thought ketone will be reduced to a secondary alcohol but in the markscheme it just had two hydrogens rather than an OH?
Question: https://ibb.co/chxpJKx4
Thanks!

It’s not a ketone - the carbonyl is bonded to a nitrogen on one end. A ketone must necessarily have the carbonyl sandwiched between two carbon atoms.

Reply 7

anonymous56754

OP

11

Original post by TypicalNerd

It is - in fact, it’s a very strong reducing agent at that. When used to reduce an amide, it will always form an amine. So basically replace the hydroxyl with a hydrogen and you have the right product

but isn't an amine nh2?

Reply 8

TypicalNerd

18

Original post by anonymous56754

but isn't an amine nh2?

That’s a primary amine. You can also get 2° amines (like the product in this example), where the nitrogen is bound to two carbons and one hydrogen and 3° amines where the nitrogen is bound to three carbons.

Reply 9

anonymous56754

OP

11

Original post by TypicalNerd

That’s a primary amine. You can also get 2° amines (like the product in this example), where the nitrogen is bound to two carbons and one hydrogen and 3° amines where the nitrogen is bound to three carbons.

I see, thank you!

Chemistry question help please

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