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    (Original post by Super199)
    Can someone explain what determines elimination or substitution?
    Elimination means things are taken away only (eliminated)...
    Substitution means things are swapped around (substituted).

    A reaction that forms a double bond (e.g. ethane into ethene) is an elimination reaction because those extra hydrogens are taken away.
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    (Original post by Super199)
    Can someone explain what determines elimination or substitution?
    If you're reacting with hydroxide which can act as a base or a nucleohphile, it acts as a base in elimination and the conditions for elimination is an ethanolic solvent, whereas with substitution the hydroxide acts as a nucleophile and you would be looking at aqueous solvents. This is because if you tried to eliminate in aqueous conditions you have an equilibrium state where you get rehydration of the double bond. So you would want to stop that from occuring, hence the ethanolic solvent.
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    (Original post by Protoxylic)
    If you're reacting with hydroxide which can act as a base or a nucleohphile, it acts as a base in elimination and the conditions for elimination is an ethanolic solvent, whereas with substitution the hydroxide acts as a nucleophile and you would be looking at aqueous solvents. This is because if you tried to eliminate in aqueous conditions you have an equilibrium state where you get rehydration of the double bond. So you would want to stop that from occuring, hence the ethanolic solvent.
    In terms of tertiary,primary and secondary which one's form elimination and which ones are nucleophillic substitution?
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    (Original post by Super199)
    In terms of tertiary,primary and secondary which one's form elimination and which ones are nucleophillic substitution?
    Do you mean if the akylhalide is primary/secondary etc? I.e. the position of the halogen
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    (Original post by Protoxylic)
    Do you mean if the akylhalide is primary/secondary etc? I.e. the position of the halogen
    The structure of the haloalkane I think?
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    (Original post by Super199)
    In terms of tertiary,primary and secondary which one's form elimination and which ones are nucleophillic substitution?
    I'll assume you do mean that. Substitution is favoured in primary alkylhalides whereas elimination is favoured in tertiary. Secondary is an equilibrium between the two. This doesn't mean that substitution DOESN'T occur, SN1 occurs on tertiary whereas SN2 occurs at secondary and primary. The same thing for elimination, E1 occurs at tertiary and E2 at primary and some secondary.
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    (Original post by Protoxylic)
    I'll assume you do mean that. Substitution is favoured in primary alkylhalides whereas elimination is favoured in tertiary. Secondary is an equilibrium between the two. This doesn't mean that substitution DOESN'T occur, SN1 occurs on tertiary whereas SN2 occurs at secondary and primary. The same thing for elimination, E1 occurs at tertiary and E2 at primary and some secondary.
    Brilliant! Thanks
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    (Original post by Super199)
    Brilliant! Thanks
    No problem!
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    For the halides and sulfuric acid I have these for NaI/KI
    NaI + H2SO4 ---> NaHSO4 + HI
    2HI + H2SO4 --> I2 + SO2 + 2H2O
    6HI + SO2 --> H2S + 3I2 + 3H2O where does the solid sulfur come into it? There are questions asking for what are the solid products and it was I2 and S but where is the solid? Thanks
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    Thanks!
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    AQA chem 2 anyone?


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    (Original post by samwillettsxxx)
    For the halides and sulfuric acid I have these for NaI/KI
    NaI + H2SO4 ---> NaHSO4 + HI
    2HI + H2SO4 --> I2 + SO2 + 2H2O
    6HI + SO2 --> H2S + 3I2 + 3H2O where does the solid sulfur come into it? There are questions asking for what are the solid products and it was I2 and S but where is the solid? Thanks
    Hello, when using potassium iodide you can have one more equation which is imbetween Hydrogen Sulfide and Sulfur dioxide.

    Sulfur is the reducing product as it has an oxidation state of 0 so it has lost electrons. It forms a yellow compound

    So basically you get another reaction
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    Hey, does anyone have the June 2014 F322 Paper?? Really need it for revision
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    Can someone help me out please. I'm confused over how alkanes release energy when burnt. I know energy is released by forming new product bonds in H2O and CO2 but that's what I don't understand. Surely energy would need to be taken in from the surroundings to make a new bond not be released??


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    Hey someone please explain free radical addition polymerisation with it's stages in detail?? I cant get my head around it I looked in the textbook, and watched videos still dont get it :/
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    Here's a useful link for those doing the OCR salters B F332 paper
    https://boswellsrcd.wikispaces.com/Year+12+AS+Chemistry
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    (Original post by SubwayLover1)
    Hello, when using potassium iodide you can have one more equation which is imbetween Hydrogen Sulfide and Sulfur dioxide.

    Sulfur is the reducing product as it has an oxidation state of 0 so it has lost electrons. It forms a yellow compound

    So basically you get another reaction
    Thank you!! So it reduces the sulfuric acid one more time from SO2, H2S then to S
    Finally someone replied lmao been stuck on that for ages
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    (Original post by samwillettsxxx)
    Thank you!! So it reduces the sulfuric acid one more time from SO2, H2S then to S
    Finally someone replied lmao been stuck on that for ages
    Yep

    I remember it from So2 to S then H2S because Sulfur has a negative oxidation state in hydrogen sulphide
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    (Original post by SubwayLover1)
    Yep

    I remember it from So2 to S then H2S because Sulfur has a negative oxidation state in hydrogen sulphide
    my cgp aqa book has missed out the stage where just solid sulfur was formed for some reason! Thank you
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    I need help I do OCR salters B and its a question about Nucleophiles
    I was wondering whether in all nucleophilic substitutions whether reflex is required and heating it under NaOH or is it only when a hydroxide substitutes the halogenoalkane.

    Thanks
 
 
 
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