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A-level Paper 2 OCR chemistry 2019 11th June unofficial mark scheme

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The last one was NMR was a carboxylic acid

Original post by aarks the sharks

Bois,

I think all of you messed up, I go to Eton and all of you are wrong xxx

I got an aldehyde for the structure for the last one btw.

This Ieuan Hughes btw search me up on FB

Reply 181

RedGiant

Original post by MIKESPIKE10

I said to use K2Cr2O7/H+ under distillation conditions and there is only a colour change in one (the alcohol) is this ok?

I'd have thought so, yeah.

Reply 182

Ishimagine

I think in the IR spectra there was a broad peak between 2500 and 3300 which corresponds to an OH group in a carboxylic acid

Original post by whitemad12

anyone else not get the structure of the carboxylic acid in the proton NMR!? im panicking but i got the formula right

Original post by Gc31

What structure did people get on the final 6 marker? Did it matter about the positions on the benzene ring because it didn't give us carbon NMR??

I just assumed they'd be opposite one another but it said there were multiple possible structures to choose from so I'm guessing it didn't matter.

Reply 185

chidz1234

Original post by Hcst

I did but they are saying it is wrong

Same I got this aswell. I dunno how the answer was 22.5g , I fully thought I got it right :frown:

Me too

With the hydrolysis of the ester Q, when hydrolysed using excess OH-, did people say that the Bromine was replaced with a hydroxyl group, on the carboxylic acid?

Reply 188

username3191094

Got that too

Original post by mitchell.

24018 for 200 molecules of polyester

Reply 189

Danielle D

I got that too lool but everyone else got 22.5g eek

Original post by Tom Ballinger

31.88 I think didn't know what I was doing though

Reply 190

iniinininin

how can mass be 3.6 if ur making 12.75g with a 40% yield?

Original post by chidz1234

Same I got this aswell. I dunno how the answer was 22.5g , I fully thought I got it right :frown:

Reply 191

MIKESPIKE10

CH3 has a 2,4- directing effect so conventionally CH(CH3)COOH wouldn't ever be in position 3. But the multiplet didn't have the normal peak for 1,4 substitution on benzene so it wouldn't have been 1, 4 substituted benzene and would've been a 1,2 subbed.

Original post by RedGiant

This was the correct structure, although the -CH3 group on the benzene ring could have been anywhere:

https://imgur.com/nm7XVsX

Reply 192

Levi23317

Original post by tahir6504

Did anyone get 24018 for the molar mass of the 200 polymer

Yepp. I bet alot of people forgot about the extra OH and H on the ends of the polymer and got 24000 tho.

Reply 193

SkylineS4

Yea, the question after asked what reactions happened. So it was substitution and hydrolysis.

Original post by Themclarenoscar

With the hydrolysis of the ester Q, when hydrolysed using excess OH-, did people say that the Bromine was replaced with a hydroxyl group, on the carboxylic acid?

Reply 194

annnnnnnnnnnee

For the last one I got an aldehyde and an alcohol group on the benzene ring

Reply 195

jason0597

Original post by 12kayase

Click the link below to see the structure:
https://imgur.com/nm7XVsX

You can use bbcode tags to embed the image directly into the OP
Replacing the link above with the direct source of the image in img tags yields the following: