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    (Original post by keisiuho)
    ......
    I put heat only.......
    then nvm
    you`ll get 1 point
    but if you put dissolved in ethanol,another point
    bear in mind that this is for the elimination reaction
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    Hey, For EDEXCEL Unit 2 paper... there was a question that asked to you to prove that an emperical formula was C2H9N... the next question went on about what the reagent and conditions were. I put down that Potassium Cyanide was needed, but my friend says conc. Ammonia.... I think he;s right...what did you get for that question???


    Also, in the unit 3 paper, the last part of question 1.. it asked to distinguish between solide sodium bromide and solid sodium chloride (i think). would the answer be that Chloride gas is given off (for sodium chloride upon adding conc. H2SO4) and that it turns damp blue litmus paper red and then bleaching it. And for NaBr; Brown gas of Bromine given off that also turns damp litmus paper red but does not bleach it... I think the second part is wrong . Also, do you think that i lost a few marks on the same paper (for the last question) by not putting that a stop watch was needed....
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    (Original post by Mathemagician)
    Hey, For EDEXCEL Unit 2 paper... there was a question that asked to you to prove that an emperical formula was C2H9N... the next question went on about what the reagent and conditions were. I put down that Potassium Cyanide was needed, but my friend says conc. Ammonia.... I think he;s right...what did you get for that question???


    Also, in the unit 3 paper, the last part of question 1.. it asked to distinguish between solide sodium bromide and solid sodium chloride (i think). would the answer be that Chloride gas is given off (for sodium chloride upon adding conc. H2SO4) and that it turns damp blue litmus paper red and then bleaching it. And for NaBr; Brown gas of Bromine given off that also turns damp litmus paper red but does not bleach it... I think the second part is wrong . Also, do you think that i lost a few marks on the same paper (for the last question) by not putting that a stop watch was needed....
    for that unit 2 question
    that compound was a primary amine,therefore the reagents are aq,ammonia in an ethanolic solution,heated in a sealed tube if the conditions were asked,but it wasnt asked right?
    conc.ammonia can be used also i think

    sorry cant help you with unit 3 cause i didnt do it
    but ill try
    if you add conc.H2SO4....steamy fumes of HCL will be produced for NaCl and changes damp litmus paper red.
    And for NaBr...Hbr will be produced.
    thats how to distinguish them
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    (Original post by MalaysianDude)
    for that unit 2 question
    that compound was a primary amine,therefore the reagents are aq,ammonia in an ethanolic solution,heated in a sealed tube if the conditions were asked,but it wasnt asked right?
    conc.ammonia can be used also i think

    sorry cant help you with unit 3 cause i didnt do it
    but ill try
    if you add conc.H2SO4....steamy fumes of HCL will be produced for NaCl and changes damp litmus paper red.
    And for NaBr...Hbr will be produced.
    thats how to distinguish them
    does it bleach or turn red? ppl say bleach... o crap.

    btw not hbr... thats the first step and not the final product... and they are SO2, Br2 and H2O.
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    (Original post by MalaysianDude)
    for that unit 2 question
    that compound was a primary amine,therefore the reagents are aq,ammonia in an ethanolic solution,heated in a sealed tube if the conditions were asked,but it wasnt asked right?
    conc.ammonia can be used also i think

    sorry cant help you with unit 3 cause i didnt do it
    but ill try
    if you add conc.H2SO4....steamy fumes of HCL will be produced for NaCl and changes damp litmus paper red.
    And for NaBr...Hbr will be produced.
    thats how to distinguish them
    No, but wouldnt HBr also turn damp litmus paper red to an extent?
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    (Original post by z!D4N)
    does it bleach or turn red? ppl say bleach... o crap.

    btw not hbr... thats the first step and not the final product... and they are SO2, Br2 and H2O.
    it turns red and then bleaches.... that question was worth like 5 marks so I think that you had to mention both points
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    (Original post by z!D4N)
    does it bleach or turn red? ppl say bleach... o crap.

    btw not hbr... thats the first step and not the final product... and they are SO2, Br2 and H2O.
    are you sure?
    cause i know that if you add conc.H2SO4 into a chlorine compount,HCL will be produced...
    I dont think HCl decolorises litmus paper

    but oh well...nvm about that
    it has been sometime since i last revised my unit 3
    oh well
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    (Original post by MalaysianDude)
    are you sure?
    cause i know that if you add conc.H2SO4 into a chlorine compount,HCL will be produced...
    I dont think HCl decolorises litmus paper
    the test was stated in the question "Add conc. H2SO4 to solid NaCl and NaBr and test with damp blue litmus paper" so it must had something to do with bleaching otherwise there will only be 4 points mentioned out of 5....
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    (Original post by z!D4N)
    does it bleach or turn red? ppl say bleach... o crap.

    btw not hbr... thats the first step and not the final product... and they are SO2, Br2 and H2O.
    Not all HBr is oxidized
    So they are SO2, Br2, HBr (you dont have to mention H2O)
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    (Original post by Mathemagician)
    the test was stated in the question "Add conc. H2SO4 to solid NaCl and NaBr and test with damp blue litmus paper" so it must had something to do with bleaching otherwise there will only be 4 points mentioned out of 5....
    Which can bleach the paper?
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    (Original post by keisiuho)
    Not all HBr is oxidized
    So they are SO2, Br2, HBr (you dont have to mention H2O)
    lol, SO2 is acidic anyway.
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    [QUOTE=keisiuho]Which can bleach the paper?QUOTE]
    Chlorine gas
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    (Original post by z!D4N)
    lol, SO2 is acidic anyway.
    yes
    Also HBr is a stronger acid than HCl
    so it will turns red at first away

    But i dont know if it will be bleached
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    (Original post by Mathemagician)
    Chlorine gas
    Conc. sulphuric acid is not strong enough to oxidise chloride to chlorine
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    (Original post by keisiuho)
    yes
    Also HBr is a stronger acid than HCl
    so it will turns red at first away

    But i dont know if it will be bleached
    no, it says in my text book that Chlorine will bleach damp litmus paper after turning it red..
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    (Original post by keisiuho)
    yes
    Also HBr is a stronger acid than HCl
    so it will turns red at first away

    But i dont know if it will be bleached
    my friends say that... im not sure.
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    (Original post by Mathemagician)
    no, it says in my text book that Chlorine will bleach damp litmus paper after turning it red..
    Yes.
    But there is no chlorine produced
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    (Original post by keisiuho)
    Yes.
    But there is no chlorine produced
    yups i agree..
    how can there be a decolorisation
    it should just change from blue to red
    and thats it
    just mention that its a white fume which changes damp blue litmus paper into red
    that s it
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    maaan i soooo wished i retaken unit 1 after hearing it was easier than unit 2..
    i was laffin away in unit 2.. would put me in a much better position than i am in now :/
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    (Original post by MalaysianDude)
    yups i agree..
    how can there be a decolorisation
    it should just change from blue to red
    and thats it
    just mention that its a white fume which changes damp blue litmus paper into red
    that s it
    steamy fume actually
 
 
 
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