Help chemistry a level

Help I don’t get part B the answer is annotated underneath the q

Also for this question:

There are only 2 lines on the compound B 13c NMR so how’s there 3 different c environments??
To underlined this on the markscheme

(edited 1 year ago)

Reply 1

George H.

For your first question, each spectrum has 1 peak created by CH₂, which can be identified by being smaller than the ones created by CH₃s and having different splitting to the CH₃s. The CH₂ in molecule A is next to a C and the CH₂ in molecule B is next to an O, so they will have different chemical shift positions. I think that's what the mark scheme is getting at.

For your second question, I don't know why it says there are 3 peaks either.

Reply 2

charco

Study Forum Helper

Original post by Alevelhelp.1

Help I don’t get part B the answer is annotated underneath the q

Also for this question:

There are only 2 lines on the compound B 13c NMR so how’s there 3 different c environments??
To underlined this on the markscheme

B only has two different ¹³C environments (as can be seen also in the spectrum), whereas A has 3 different environments.