AQA Jan 2012 Paper 2 Q8 (with explained solutions) |

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AQA Jan 2012 Paper 2 Q8

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do not write outside the box it is possible to convert but ene into its structural isomer but ene a state the type of structural isomerism shown by but ene and but ene mark b the first stage in this conversion involves the reaction of hydrogen bromide with but ene ch ch ch ch hbr ch ch chbrch outline a mechanism for this reaction c the second stage is to convert bromobutane into but ene ch ch chbrch koh ch ch chch kbr h o outline a mechanism for this reaction marks marks wmp jan chem

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question a b mark scheme general certificate of education a level chemistry unit chemistry in action january marking guidance position al isomerism m must show an arrow from the double bond towards the h atom of the h br molecule m must show the breaking of the h br bond m is for the structure of the secondary carbocation m must show an arrow from the lone pair of electrons on the negatively charged bromide ion towards the positively charged carbon atom of either a primary or secondary carbocation nb the arrows here are double headed mark comments penalise one mark from their total if half headed arrows are used m ignore partial negative charge on the double bond m penalise partial charges on h br bond if wrong way and penalise formal charges penalise m if there is a bond drawn to the positive charge penalise once only in any part of the mechanism for a line and two dots to show a bond maximum any of marks for wrong reactant or primary carbocation if br is used maximum marks for their mechanism do not penalise the use of sticks c mark scheme general certificate of education a level chemistry unit chemistry in action january m must show an arrow from the lone pair on oxygen of a negatively charged hydroxide ion to a correct h atom m must show an arrow from a c h bond adjacent to the c br bond towards the appropriate c c bond only award if an arrow is shown attacking the h atom of an adjacent c h in m m is independent provided it is from their original molecule award full marks for an e mechanism in which m is on the correct carbocation nb the arrows here are double headed penalise one mark from their total if half headed arrows are used penalise m if covalent koh penalise m for formal charge on c of the c br or incorrect partial charges on c br penalise m if an extra arrow is drawn from the br of the c br bond to for example k ignore other partial charges penalise once only in any part of the mechanism for a line and two dots to show a bond maximum any of marks for wrong reactant or wrong product if shown or a mechanism that leads to but ene accept the correct use of sticks for the molecule except for the c h being attacked

Question 1 2 3 4 5 6 7 8 9 10

Topics to revise

AQA > Organic Chemistry > Alkenes AS >

3 Electrophilic addition

AQA > Organic Chemistry > Optical isomerism >

1 Optical isomerism

AQA > Organic Chemistry > Carboxylic acids and derivatives >

2 Esterification and hydrolysis of esters

AQA > Physical chemistry > Atomic structure AS >

4 Electronic arrangement

AQA > Physical chemistry > Thermodynamics >

3 Trends in Lattice Enthalpy

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