MJC H2 Chem 2013 Prelim P3 QP

©chemistry@meridian jc Name ________________________ Class: ___________ Reg Number: _____ MERIDIAN JUNIOR COLLEGE JC 2 Preliminary Examination Higher 2 _________________________________________________________________________ Chemistry 9647 Paper 3 Free Response 17 Sep 2013 2 hours Additional Materials: Data Booklet Writing Paper _________________________________________________________________________ INSTRUCTIONS TO CANDIDATES Write your name, class and register number in the spaces provided at the top of this page. Answer 4 out of 5 questions in this paper. Begin each question on a fresh page of writing paper. Fasten the writing papers behind the given Cover Page for Questions 1 & 2 and Cover Page for Questions 3, 4 & 5 respectively. Hand in Questions 1 & 2 and 3, 4 & 5 separately. You are advised to spend about 30 min per question only. INFORMATION FOR CANDIDATES The number of marks is given in brackets [ ] at the end of each question or part question. You are reminded of the need for good English and clear presentation in your answers. This document consists of 18 printed pages and 4 blank pages 923

©chemistr 1 (a) (b) ry@meridian jc Be Antihistam body. The eyes expe A sample 57.6 cm3 o 1 atm. (i) Calcu abov (ii) The a betw (iii) Hen c fexof Fexofenad contains 1 per intake (i) Sugg the fe Answer a egin each mines are c e drug fexo erienced by RR HO of 1 g of f of NO2 gas ulate the M ve informat actual Mr o een the ca ce, sugges fenadine, R dine is so 120 mg of and twice gest why fe exofenadin any 4 out question o consumed ofenadine i y hay fever N R Fe fexofenadi s was prod Mr of fexofe ion. of fexofena alculated M st the struc R2C20H29O4 ld as the the hydro daily for a exofenadin ne form. 1 of 5 quest on a fresh to reduce is used to r sufferers, OH exofenadi R is ine was c o duced. All v enadine, to adine is 50 Mr in (a)(i) a ctural formu 4N. hydrochlo ochloride s an average ne is sold a tions in th sheet of w the effects treat snee , without ca H ine s common ompletely b volumes w o the neare 01. Explain and the act ula of the c oride salt alt. The m e 65 kg adu as the hydr his paper. writing pape s of allergi ezing, runn ausing dro COOH organic hy burnt in e x were measu est whole n why there tual Mr. common o in tablet f maximum d ult. rochloride s [Turn o er. ic reaction ny nose a n owsiness. ydrocarbon xcess oxyg ured at 80 number, us e is a discr organic gro form. Eac h dosage is 4 salt rather over s in the nd itchy n group gen and oC and sing the repancy oup R in [5] h tablet 490 mg r than in 924

2 ©chemistry@meridian jc [Turn over (ii) Calculate the number of boxes of tablets (refer to the photograph on page 2) a traveller needs to carry for a 5 day journey if he is going to consume it up to the safety limit so as to maximise his runny nose recovery. [3] In pharmaceutical companies, fexofenadine can be synthesised in the following way. CN CN OH Cl NH R HO CH3Br R COOH N RR HO OH Fexofenadine HCl (aq), heat I II B CN CNCH3Br A ClCl O AlCl3 III R2C20H28N2O2     (c) (i) Draw the structural formula of compounds A and B. (ii) State the type of reaction for II. (iii) Suggest the reagent and condition for III. (iv) Draw the structure of the product formed when a sample of the intermediate given below was heated with aqueous K 2Cr2O7 in D 2SO4. (D, deuterium = 2H) CN OH Cl   925

3 ©chemistry@meridian jc [Turn over (v) Fexofenadine can be converted into a cyclic compound shown below. Suggest the reagent and condition for this conversion. [6] N R R O HO O (d) In a separate experiment, the precursor for the synthesis of fexofenadine, was found to react with one mole of bromine to form (i) Outline a mechanism to show how the above product could have been formed.   (ii) Suggest why it is not possible to synthesise the iodo derivative, from the same precursor when some I 2 is present. [4] (e) Compound B, with the molecular formula R2C20H28N2O2, contains two different nitrogen-containing functional groups. Name and explain which functional group has a higher Kb value. [2]   [Total: 20] CN Br CN I CN 926

©chemistr 2 (a) ( (b) ry@meridian jc In a direc t takes plac propanone membrane the electr o produce e (i) Ded u overa (ii) A ty p Book half-c (iii) Expla when half-c (iv) Sugg One meth of platinum consists o electrolyte (i) Sugg react (ii) Calcu of 25 for 75 t propan-2 ce catalytic e and hyd r e (PEM) to ons travel lectrical po uce the ion all cell reac pical D2P F klet, calc u cell. ain qualit a n a small cell. gest one di od for the m onto the of a soluti e cell. gest the h tion. State ulate the m 5 cm2 if a c 5 minutes. -ol fuel ce cally at tem rogen ions o the electr through t ower. n-electron h ction during FC batter y ulate the atively the amount o f sadvantag constructio surface of on of [Pt ( half-equati an observ mass of pla current of 3 4 ell (D2PFC mperatures s. H+ ions t rode to rea the extern a half equati g discharg y generat e Eθ value in change i f base is ge of using on of the f f the PEM (NH3)4]2+ a on includ vation. atinum dep 3.5 x 10-3 A ), the ele c around 80 travel thro act with oxy al electric a ion for the ging. es about 1 nvolving t n the ov e added to this fuel c fuel cell inv . The elect and the P ing state posited ont A cm-2 was ctro-oxidatio 0 oC. The p ugh the p o ygen to pro al circuit t anode an 1.26 volts . the prop a erall Eθ cell the prop a cell. volves elec trolyte use PEM is th e symbols to a PEM s passed t [Turn o on of pro p process pr olymer ele oduce wate to the cat h d hence w . Using t h an-2-ol/pro value me an-2-ol/pro ctroplating ed for this p e cathod e for the c with surfac through the over pan-2-ol roduces ectrolyte er while hode to write the he Data panone easured panone [6] a layer process in the cathode ce area e circuit [4] 927

5 ©chemistry@meridian jc [Turn over (c) Aromatic compounds P and Q are alternative fuels used in similar fuel cells that utilise PEM. (i) The aromatic organic compounds P and Q are isomers of each other with the molecular formula C9H8O2. P produces effervescence with NaHCO 3 but Q does not. P and Q decolourise aqueous chlorine readily to form R (C 9H9O3Cl) and S (C9H7O3Cl3) respectively. Q reacts with Tollen’s reagent but not with Fehling’s solution. P and Q reacts with hot acidified potassium manganate (VII) to form T and U respectively. COOH COOH UT COOH HO Suggest the structures of P, Q, R and S, explaining the reactions involved. (ii) Aromatic compounds V and W are isomeric to compounds P and Q. Compounds V and W can be distinguished via the addition of a single reagent. Write a balanced equation to illustrate the positive test. (iii) Under appropriate conditions, compound T is converted into two isomers X and Y. COOH COOH YX Br Br Predict and explain which compound X or Y has a higher acid strength. [10] [Total: 20] 928

6 ©chemistry@meridian jc [Turn over 3 Azides are energy-rich molecules with m any applications. Sodium azide, for example, is used as a preservative , mutagen, biocide, and assay reagent. Organic azides and hydrogen azides are important starting materials capable of producing a diversity of organic compounds. In the Schmidt rearrangement reacti ons shown below, hydrogen azide, HN 3, can be converted to the following products using acid as a catalyst (cat). nitrile aldehyde amide imine olefin amine carboxylic acid 3o alcohol imine R R N R R N R R R R R R R N H O R R O R OH O R R O R H N H R H OH R RR N CR HN3 (H+ as cat.) ketone (