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    (Original post by otrivine)
    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.


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    (Original post by MathsNerd1)
    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.


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    1) Firslty, nitration has to take place in whcih bezene reacts with conc HNO3 and conc h2so4 act as catalyst and temperature of 50 degrees. This causes a nitrobenzene to form.

    Nitrobenzene is converted into phenylamine by heating under reflux with a mixture of Sn and followed by neutralisation of concentrated HCL. Therefore, phenylamine is formed.

    Phenylamine undergoes Diazotisation in which is causes the formation of benzenediazonium chloride (ion) , before it happens HNO2 must be present and is generated in-situ. The phenylamine reacts with cold nitrous acid temp <10 and reacts with HCL and forms the diazonium ion.

    Then coupling reaction takes place in which diazonium ion reacts with phenol under alkaline conditions usually with aq NaOH and forms the azo dye with functional group N=N forming and then as a product Nacl is formed and water.

    The product gives colouring.

    2)water? it cant be NaOH because it would be 0- and Na+ and so charge would cancel?
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    (Original post by Gulzar)
    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?
    hey how are u long time no revision?

    up for some on chapters 1 and 2
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    (Original post by MathsNerd1)
    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.


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    Hi buddy want to revise
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    (Original post by otrivine)
    Hi buddy want to revise
    Lets go!


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    (Original post by MathsNerd1)
    Lets go!


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    ok you start first
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    (Original post by otrivine)
    ok you start first
    This or the other unit?


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    (Original post by MathsNerd1)
    This or the other unit?


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    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
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    (Original post by otrivine)
    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)


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    (Original post by MathsNerd1)
    Okay then, that seems fair :-)

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


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    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.
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    (Original post by otrivine)
    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


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    (Original post by MathsNerd1)
    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


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    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
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    (Original post by otrivine)
    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?


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    (Original post by MathsNerd1)
    It's all good and am I allowed to do the nitration part first?


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    Yep you can do either
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    (Original post by otrivine)
    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.


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    (Original post by MathsNerd1)
    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.


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

    My turn
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    (Original post by otrivine)
    Beautiful and well structured! Happy to give you full marks.

    My turn
    Thanks, that's what I like and need to hear!

    Define electrophilic substitution and explain the mechanism of electrophilic substitution (4)


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    (Original post by otrivine)
    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.


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    (Original post by MathsNerd1)
    Very good, that's all correct and you also remembered the catalyst being reproduced at the end as well.


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    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)
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    (Original post by otrivine)
    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)
    Okay do the colour change for the acidified potassium dichromate (VI) goes from orange to green when it's reduced.

    Secondly when cyclohexane reacts with bromine water the colour changed from orange to colourless and the mechanism is electrophilic addition.


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