Edexcel Jun 2016 (IAL) Paper 3 Q (with explained solutions) |

Skip to content

Edexcel Jun 2016 (IAL) Paper 3 Q

Answers available below

2 The skeletal formulae of three organic compounds, E, F and G, are shown in the table. OH (a) Name compound E. (1)(b) Give a chemical test and its result that could be used to show the presence of the OH group in E. (2) TestResult(c) Give a chemical test and its result that could be used to show the presence of the iodine atom in F. (2) TestResult(d) A few drops of G are shaken with 2 cm3 of a dilute aqueous solution of potassium manganate(VII) acidified with dilute sulfuric acid. (i) State the colour change that occurs in this reaction. (1) Fromto*P46663A0416*<br />
(ii) Draw the skeletal formula of the organic product of this reaction. (e) State the reagent and give the essential conditions for the conversion of F to G. (1) (2) ReagentConditions(f) A student attempted to convert G to F using a standard method involving the addition of hydrogen iodide, HI, prepared in situ. However, very little of F was formed. (i) Draw the structure of the major product obtained by the student. (1) (1) (ii) Explain, by referring to the intermediate in the mechanism of the reaction, why F is only a minor product.*P46663A0516* Turn over<br />
(g) Compound E may be oxidized with potassium dichromate(VI) acidified with sulfuric acid, using the apparatus shown below. For clarity, clamps, stands and rubber tubing have been omitted from the diagram.Liebig condenserreaction mixture round bottom flask(i) Complete the labelling of this diagram. heat (ii) Name the technique that is carried out using this apparatus. (2) (1)(iii) Explain how the Liebig condenser works and its purpose in the apparatus shown. (2)*P46663A0616*<br />
(h) Oxidation of E can result in the formation of an aldehyde or a carboxylic acid. OH (i) Give the skeletal or displayed formulae of these products. Aldehyde Carboxylic acid (ii) By considering the bonds in these two products, explain how infrared spectroscopy can be used to distinguish between them. You are not expected to give specific wavenumbers. (2) (1)*P46663A0716* Turn over<br />
(i) The carboxylic acid produced by the oxidation of E is an oily liquid which boils at 206C. The carboxylic acid may be obtained from the reaction mixture by distillation. (i) Name the three additional pieces of apparatus, apart from clamps and stands, which are essential to convert the apparatus shown at the start of part (g) for distillation. (3) 1.2.3.(ii) Suggest a suitable temperature range over which to collect the carboxylic acid distillate. (1)(iii) The distillate contains a trace of water. Suggest a drying agent that could be used to remove this. (1)(Total for Question 2 = 24 marks) *P46663A0816*<br />
BLANK PAGE *P46663A0916* Turn over<br />

Show answer

Acceptable Answer Hexan-1-ol ALLOW Hexane-1-ol / 1-Hexanol If two or more names are given, all must be correct Reject Hexanol Hexen-1-ol Hexa-1-ol Hex-1-ol Acceptable Answer Any test (1) corresponding result (1) MP2 dependent on MP1 Mark (1) Mark (2) Reject Phosphorus(III) chloride / phosphorus trichloride / PCl3 Just smoke Smoke Just Na2Cr2O7 / K2Cr2O7 (no acid) Test Add phosphorus(V) chloride / phosphorus pentachloride / PCl5 Add thionyl chloride / SOCl2 Add sodium / Na Result Steamy / misty / white fumes OR White smoke and with ammonia Steamy / misty / white fumes Effervescence / bubbling / fizzing IGNORE white solid formed sodium dissolved Sweet / fruity / pear drops smell Add ethanoic acid and a mineral acid and warm ALLOW PCl5 solution, unless unsuitable solvent (e.g. water) when max 1 (for result) ALLOW for 1 mark Acidified sodium or potassium dichromate((VI)) / Na2Cr2O7 / K2Cr2O7 turns from orange to green / blue If product is tested, test and result must be fully correct Question Number 2(a) Question Number 2(b)<br />
Acceptable Answer MP2 dependent on mention of silver nitrate First mark Add (aqueous ethanol solution of) silver nitrate / AgNO3 (and nitric acid) OR Add NaOH, (then) HNO3 and (followed by) silver nitrate / AgNO3 (1) Second mark Yellow precipitate ALLOW Yellow solid / crystals (1) IGNORE Heat Addition of ammonia to precipitate If product is tested, test and result must be fully correct Mark (2) Reject Other acids Other acids Just turns yellow Tests for iodine (scores (0)) Acceptable Answer From pink / purple to colourless IGNORE clear dark Acceptable Answer Penalise bond to OH only when it is clearly to the H atom Reject Red Mark (1) Mark (1) Reject Displayed or structural formulae H atoms on carbons of skeletal formula Question Number 2(c) Question Number 2(d)(i) Question Number 2(d)(ii)<br />
Question Number 2(e) Acceptable Answer These are stand alone marks (Reagent=) potassium hydroxide / KOH ALLOW Sodium hydroxide / NaOH (1) (Conditions =) Alcoholic / ethanolic solution and heat / boil / reflux / warm (1) If reagent is given as alcoholic KOH / NaOH and conditions as heat, award both marks Reject Mark (2) additional incorrect reagents Distil Question Number 2(f)(i) Acceptable Answer Reject Mark (1) Question Number 2(f)(ii) OR OR Fully displayed OR CH3CH2CH2CH2CHICH3 Acceptable Answer Secondary carbocation (formed in the first step) is more stable (than the primary) (so little F forms) OR Reverse argument Intermediate ions can be shown by structural (or other) formulae IGNORE Reference to Markovnikov's Rule Secondary product is more stable Mark (1) Reject Just intermediate Just structure cation Just carbocation more stable<br />
Question Number 2(g)(i) Water in bottom & water out top (1) Acceptable Answer anti-bumping granules ALLOW pieces of porcelain nucleation granules glass beads anti-bumping crystals (1) Question Number 2(g)(ii) Question Number 2(g)(iii) Acceptable Answer (Heat / boil under) Reflux OR Refluxing ALLOW Reflux condenser Mark (2) Reject Just arrows Anti-knock Reject Any distillation Just condensing Mark (1) Reject Mark (2) Acceptable Answer (Cold) water (passing through the condenser) (cools and) condenses the vapours /gases (rising from the reaction mixture) ALLOW Description of condensing (1) Prevents escape of reactants and products ALLOW Prevents escape of reactants / products / vapours / gases ALLOW so that the reaction / oxidation can continue to completion (1)<br />
Question Number 2(h)(i) Acceptable Answer ALLOW Aldehyde hydrogen shown OR OR Reject Mark (2) -CHO -COH -COOH (1) Both functional groups displayed and correct, but with errors on carbon chains or structural formulae used for chain scores (1) (1)<br />
Question Number 2(h)(ii) EITHER Question Number 2(i)(i) Mark (1) Reject Just reference to the bonds / groups / stretching / bending Mark (3) Reject Just flask volumetric flask Acceptable Answer Aldehyde / CHO and carboxylic acid / COOH groups will have characteristic peaks / absorptions (at different wavenumbers / frequencies) OR carboxylic acid has an OH group which absorbs at a particular frequency / OH peak ALLOW Wavelength for wavenumber / frequency carboxylic acid has an CO bond which absorbs at a particular frequency Different fingerprint regions IGNORE Reference to carbonyl / C=O group Acceptable Answer Thermometer (1) Stillhead / (3-way) adaptor (1) Conical / Erlenmeyer / collecting flask ALLOW Delivery tube beaker test / boiling tube measuring cylinder round-bottom /pear-shaped flask (1) IGNORE Stopper Side arm tube Vented tube Condenser ALLOW Diagram with appropriate labels Acceptable Answer Lower value: any value from 200 to 205(oC) Upper value: any value from 207 to 212(oC) Question Number 2(i)(ii) Mar k (1) Reject Single temperatur e<br />
Acceptable Answer (anhydrous) Calcium chloride / CaCl2 OR Magnesium sulfate / MgSO4 OR Sodium sulfate / Na2SO4 ALLOW Calcium sulfate / CaSO4 If name & formula both must be correct Mark (1) Reject Sulfuric acid / H2SO4 CuSO4 CuCl2 Silica gel Total for Question 2 = 24 marks Question Number 2(i)(iii)<br />

Question

About us | Need Help? | Feedback

Proudly powered by WordPress | Theme: Sydney by aThemes.