OCR A2 CHEMISTRY F324 and F325- 14th and 22nd June 2016- OFFICIAL THREAD

just read the book, the page about synthetic methods of aliphatic compounds have a very misleading image, which lead to a lot of people thinking that carboxylic acids could not be reduced. amuses me that they do not include it in the spec, but give questions exactly about reducing carboxylic acids in the exam lol.

but do they get reduced also by nabh4

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Reply 1561

Obi-Wan

Sorry i know this has been asked before:

What would be the splitting pattern for CH3-CH2-CH2-CH3 (Butane)?

I know there are 2 hydrogen environments due to the symmetry, but the symmentry also affects the splitting and I'm confused as to what the effect is exactly. Thanks in advance.

Reply 1562

qweening

2

Original post by ranz

but do they get reduced also by nabh4

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no not by nabh4, but another molecule we don't need to know

Reply 1563

lai812matthew

10

Original post by Obi-Wan

Sorry i know this has been asked before:

What would be the splitting pattern for CH3-CH2-CH2-CH3 (Butane)?

I know there are 2 hydrogen environments due to the symmetry, but the symmentry also affects the splitting and I'm confused as to what the effect is exactly. Thanks in advance.

triplet quartet with integration trace 3:2.

(edited 7 years ago)

Reply 1564

KB_97

10

Original post by lai812matthew

just read the book, the page about synthetic methods of aliphatic compounds have a very misleading image, which lead to a lot of people thinking that carboxylic acids could not be reduced. amuses me that they do not include it in the spec, but give questions exactly about reducing carboxylic acids in the exam lol.

Is this about reducing with nabh4? Because that only reduced carbonyl compounds (ketones and aldehydes). I asked my teacher why we can't use it for carboxylic acid and he said it wouldn't reduce it because it's no strong enough or something like that.

No you don't. Just that nh3 is in excess. I was just explaining it so you understand why. :smile:

Original post by lai812matthew

just thinking, they could ask us to suggest a suitable isotope for certain element (e.g. N,P) to perform a magnetic resonance.

Nitrogen already has an odd number of nucleons. So does P. Do you think the could ask for halogens though. Because they might throw in a molecule containing halogens for the proton name question

Reply 1565

biologyworm

1

Original post by lai812matthew

triplet quartet with integration trace 1:1 .

Wouldn't the integration be 3:2??

Reply 1566

lai812matthew

10

Original post by biologyworm

Wouldn't the integration be 3:2??

yes i got it wrong

Reply 1567

underestimate

9

Would an NH2 produce a splitting pattern?

Reply 1568

AqsaMx

5

Original post by lai812matthew

just thinking, they could ask us to suggest a suitable isotope for certain element (e.g. N,P) to perform a magnetic resonance.

What examples would you give for N and P?

Reply 1569

suibster

3

Original post by underestimate

Would an NH2 produce a splitting pattern?

It would produce a single like O-H but with an integration trace of 2.

Reply 1570

xMillnsy

1

What are the conditions for diazonium ion + phenol reaction?

Reply 1571

suibster

3

Original post by xMillnsy

What are the conditions for diazonium ion + phenol reaction?

alkaline

Reply 1572

KB_97

10

I hope they give you the integration values for the name question. It helps me so much

Reply 1573

KB_97

10

Looks like I'll finish the paper before most people on here. I'll be panicking about my answers till the rest of you come on here. I'll finish the paper at 2:15

Reply 1574

L'Evil Wolf

6

What does the 6moldm-3 HCl for 24 hours, heating under reflux do?

Reply 1575

L'Evil Wolf

6

Original post by KB_97

Looks like I'll finish the paper before most people on here. I'll be panicking about my answers till the rest of you come on here. I'll finish the paper at 2:15