OCR F324-June 2013 Chemistry

Perfect, sorry , we have 2 minutes left! one hard one please

E110 is a yellow colouring agent that is commonly added to a variety of foods. E110 contains an azo dye made from an amine and a phenol.
1) Describe how you would prepare a sample of an azo dye in the lab from an amine, a phenol and any other necessary reagents. Include in your answer essential reagents and conditions for each stage and name any functional groups formed during the process. (7)
The solubility of E110 in water can be improved by converting the phenolic -OH group into a charged -O^- group. Suggest a suitable reagent that will convert the -OH group in E110 onto an -O^- group. (1)

I hope this was hard enough, if not then I'm not too good at asking hard questions as I have so rightfully found out.


Posted from TSR Mobile

So glad this thread is up early...I was surprised how early you need to revise to get good grades :P
Anyone doing both F324 and F325?

E110 is a yellow colouring agent that is commonly added to a variety of foods. E110 contains an azo dye made from an amine and a phenol.
1) Describe how you would prepare a sample of an azo dye in the lab from an amine, a phenol and any other necessary reagents. Include in your answer essential reagents and conditions for each stage and name any functional groups formed during the process. (7)
The solubility of E110 in water can be improved by converting the phenolic -OH group into a charged -O^- group. Suggest a suitable reagent that will convert the -OH group in E110 onto an -O^- group. (1)

I hope this was hard enough, if not then I'm not too good at asking hard questions as I have so rightfully found out.


Posted from TSR Mobile

Hi buddy want to revise

Lets go!


Posted from TSR Mobile

ok you start first

This or the other unit?


Posted from TSR Mobile

lets do some on this unit then some on other unit

We do mixture of chapters 1 and 2 in F324 and chapter 1 on F325

Okay then, that seems fair :-)

Explain why because of thalidomide pharmaceutical companies are now more aware of the dangers of optical isomers (4)


Posted from TSR Mobile

Because optical isomers , are 2 non superimposable images of each other. Each of those 2 either images have different affects which could either be more harmful or more helpful. Either of those images rotate plane polarized light either clockwise or anticlockwise. Pharmaceutical companies are now separating mixtures, using transition metal complexes, biological enzymes that could lead to less side affects in medications. Also, Thalidomide was a mirror image of a complex compound that lead to devastating affects and caused mothers sickness but the other image is less dangerous.

That is correct although you could've said that it was a drug prescribed to pregnant women to prevent morning sickness and caused deformities in their developing babies, you're just too good! My turn


Posted from TSR Mobile

should have used my pharmacy experience


Give the stages of synthesis to convert a benzene to a halogen benzene to a nitration benzene (5) give all the reagents and conditions

It's all good and am I allowed to do the nitration part first?


Posted from TSR Mobile

Yep you can do either

Right okay, firstly I'll start with the nitration as the positioning of the compound is important, so I believe.

You react benzene with conc nitric acid with a conc sulphuric acid catalyst and a temperature of 50 degrees, this is called the nitration of benzene and is an electrophilic substitution reaction and produces nitrobenzene and water.

Secondly the nitrobenzene is reacted with chlorine which needs the presence of a halogen carrier for the reaction to be successful, in this case it'll be Iron(III) chloride to produce 2,4,6- nitrobenzene and 3 molecules of HCL.


Posted from TSR Mobile

Beautiful and well structured! Happy to give you full marks.

My turn

Electrophilic sub= is a mechanism in which a hydrogen atom in the benzene ring structure is replaced with a different atom or group of atom.

The following attachment is an example of Electrophilic sub

Very good, that's all correct and you also remembered the catalyst being reproduced at the end as well.


Posted from TSR Mobile

thanks !


1) State the colour change when dichromate ions are reduced (2)

2) State the colour change when cyclohexene reacts with bromine and state the name of the mechanism (4)