OCR A Jun 2016 Paper 2 Q1 (with explained solutions) |

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OCR A Jun 2016 Paper 2 Q1

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Answer all the questions. 1 Compound A is an unsaturated hydrocarbon that can be used as the starting material for the production of organic compounds. compound A (a) What is the molecular formula of compound A?[1] (b) The flowchart shows three addition reactions of compound A. (i) In the boxes below, show the structures of the organic products formed in the reactions. Br2 H2/Ni compound A H2O mixture of isomers [4] (ii) What are the essential conditions for the reaction of compound A with H2O?[2]OCR 2016<br />
(iii) Using curly arrows, outline the mechanism for the reaction of compound A with Br2. (iv) Name the mechanism in part (iii).[1] [Total: 11] [3]OCR 2016 Turn over<br />

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F322 Question 1 (i) 1 (a) (b) Answer C7H12 (cid:57) Product from Br2 Br Br (cid:57) Product from H2/Ni (cid:57) Mixture of isomers from H2O (b) (ii) Steam OR temperature100 C (cid:57) OH (cid:57) acid (catalyst) (cid:57) Mark scheme June 2016 Marks 1 4 Guidance ALLOW correct structural OR displayed OR skeletal formula OR mixture of the above IGNORE names WATCH for missed methyl stick ALLOW added H shown, i.e. ALLOW in either order ALLOW H2O(g) IGNORE pressure IGNORE High temperature / reflux ALLOW H+ / named mineral acid / H2SO4 / H3PO4 DO NOT ALLOW weak acid e.g. ethanoic acid OH (cid:57)<br />
Mark scheme June 2016 Marks Answer Curly arrow from double bond to Br of BrBr (cid:57) (cid:3) Correct dipole shown on BrBr AND curly arrow showing breaking of BrBr bond (cid:57) (cid:71)(cid:14) Br (cid:71)(cid:16) Br ------------------------------------------------------------------------ Correct carbocation with + charge on C AND curly arrow from Br to C+ of carbocation (cid:57) OR Br Br Br Note: + andare fine for charge (circles used for clarity) Br Guidance ANNOTATE ANSWER WITH TICKS AND CROSSES Curly arrow must start from bond and go to correct atom DO NOT ALLOW any other partial charges e.g. shown on C=C bond DO NOT ALLOW + on C of carbocation. IF C atoms are displayed IGNORE missing bonds to H atoms Curly arrow must come from a lone pair on Br OR from the negative sign of Br ion (then lone pair on Br ion does not need to be shown) F322 Question 1 (iii) (b) (b) (iv) electrophilic addition (cid:57) 1 11 Total<br />

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