AIEEE 2008 Chemistry

Transcription

1 AI 008 Chemistry General Instructins There are bjective type questins with fur ptins having single crrect answer (b) Fr each incrrect respnse, ne furth (/4) f the ttal marks alltted t the questin wuld be deducted (c) N deductin frm the ttal scre will, hwever, be made if n respnse is indicated fr an item in the answer sheet (d) The candidates are advised nt t attempt such item in the answer sheet if they are nt sure f the crrect respnse (e) Mre than ne answer indicated against a questin will be deemed as incrrect respnse and will be negatively marked The rganic chlr cmpund, which shws cmplete sterechemical inversin during a N reactin, is (C 5 ) C (b) (C ) C (c) (C ) C (d) C (d) teric hindrance is the majr factr cnsidered fr a substrate underging N reactin In C, the hindrance being minimum favrs N t a maximum extent Tluene is nitrated and the resulting prduct is reduced with tin and hydrchlric acid The prduct s btained is diaztized and then heated with cuprus brmide The reactin mixture s frmed cntains mixture f - and p-brmtluenes (b) mixture f - and p-dibrmbenzenes (c) mixture f - and p-brmanilines (d) mixture f - and m-brmtluenes C C Tluene (rth and para directing) Nitratin n/ C C NaN / N N N C N n/ C N NaN / C (Diaznium salt) CuBr/Br N C Br andmeyer s reactin C Br JD Lee, lmns & Fryhle Fundamentals f Chemistry Textbk fr ass Cpyright 0 Wiley India Pvt Ltd All rights reserved

2 AI 008 The crdinatin number and the xidatin state f the element in the cmplex [(en) (C 4 )]N (where (en) is ethylenediamine) are, respectively, and (b) 4 and (c) 4 and (d) and (d) en is a neutral ligand, bidentate C 4 has a ( ) charge and is again bidentate Therefre, the crdinatin number = and xidatins state = 4 Identify the wrng statements in the fllwing: Chlrflurcarbns are respnsible fr zne layer depletin (b) Greenhuse effect is respnsible fr glbal warming (c) zne layer des nt permit infrared radiatin frm the sun t reach the earth (d) Acid rain is mstly because f xides f nitrgen and sulphur (c) zne layer des allw infrared radiatin frm sun t reach the earth Thugh zne layer des nt allw UV radiatin 5 Phenl, when it first reacts with cncentrated sulphuric acid and then with cncentrated nitric acid, gives,4,-trinitrbenzene (b) -nitrphenl (c) p-nitrphenl (d) nitrbenzene (b) The grup is rth and para directing, but grup being bigger preferably ccupies the para psitin cnc 4 cnc N (-nitrphenl) N In the fllwing sequence f reactins, the alkene frms the cmpund B CC CC A = B Zn The cmpund B is C C C (b) C CC (c) C C CC (d) C C (d) This is an example f reductive znlysis: C C C C C C C C (znide) C B A C /Zn ( mles) 7 Larger number f xidatin states are exhibited by the actinids than thse by the lanthanids, the main reasn being 4f rbitals are mre diffused than the 5f rbitals (b) lesser energy difference between 5f and d than between 4f and 5d rbitals (c) mre energy difference between 5f and d than between 4f and 5d rbitals (d) mre reactive nature f the actinids than the lanthanids (b) Lesser energy difference between 5f and d than 4f and 5d rbitals, results in larger number f xidatin state by actinids 8 In which f the fllwing ctahedral cmplexes f C (at n 7), will the magnitude f D be the highest? [C(CN) ] (b) [C(C 4 ) ] (c) [C( ) ] (d) [C(N ) ] D is called as CF and depends upn the nature f ligand CN - being strngest ligand, D is the highest 9 At 80 C, the vapr pressure f pure liquid A is 50 mm g and that f pure liquid B is 000 mm g If a mixture slutin f A and B bils at 80 C and atm pressure, the amunt f A in the mixture is ( atm = 70 mm g) is 5 ml % (b) 4 ml % (c) 48 ml % (d) 50 ml % (d) Accrding t Rault s law pt = paxa pbxb 70 = 50xA pb ( xa) xa = 05 Thus, mle% f A = = 50% 0 Fr a reactin A B, rate f disappearance f A is related t the rate f appearance f B by the expressin = (c) = d[b] d[b] (b) = (d) = d[b] 4 d[b] 4 (b) In the reactin A B Fr instantaneus rates, dx d[b] = = dx d[b] = = 4 The equilibrium cnstants K p and K p fr the reactins X Y and Z P Q, respectively, are in the rati f : 9 If the degree f dissciatin f X and Z be equal then the rati f ttal pressure at these equilibria is : (b) : (c) : (d) :9 X Y 0 ( a) a K p = ( a ) P ( a) a JD Lee, lmns & Fryhle Fundamentals f Chemistry Textbk fr ass Cpyright 0 Wiley India Pvt Ltd All rights reserved

3 AI 008 Nw, K K Z P Q 0 0 ( a ) a a p p K = 9 Therefre, p = x p ( a) a 4 p p = = p 9 p xidizing pwer f chlrine in aqueus slutin can be determined by the parameters indicated belw: diss in hyd ( g) (g) ( g) ( aq ) The energy invlved in the cnversin f t g = 40 ( g), ( ) (using the data, diss kjml in hyd = 49 kj ml, =8kJ ml ) will be 5 kj ml (b) 0 kj ml (c) 850 kj ml (d) 0 kj ml (b) Fr the reactin ( g) ( aq); = = = 0 kj ml Which f the fllwing factrs is f n significance fr rasting sulphide res t the xides and nt subjecting the sulphide res t carbn reductin directly? Metal sulphides are thermdynamically mre stable than C (b) C is thermdynamically mre stable than C (c) Metal sulphides are less stable than the crrespnding xides (d) C is mre vlatile than C 4 Bakelite is btained frm phenl by reacting with (C ) (b) C C (c) C CC (d) C (d) Bakelite is a crss-linked plymer f phenl and C C C C Plymerize C 5 Fr the fllwing three reactins I, II and III, equilibrium cnstants are given: (I) C(g) (g) C (g) (g) K (II) C 4(g) (g) C(g) (g) K C n (III) C 4(g) (g) C(g) 4 (g) K Which f the fllwing relatins is crrect? K K = K (b) K K = K (c) K = K K (d) KK = K (c) Frm reactin (III) 4 C K =, C4 which can be btained by K K [As q (I) and q (II) when added give q (III)] The abslute cnfiguratin f C C is, (b) R, R (c) R, (d), R (b) The mlecule can be represented as C 4 C ence R, R and ptically active 7 The electrphile, attacks the benzene ring t generate the intermediate s cmplex f the fllwing, which s cmplex is f lwest energy? N (b) (c) N (d) N (b) An electrn-withdrawing grup like N will tend t withdraw electrns frm the ring and hence destabilize the s cmplex 8 a -D-()-glucse and b -D-()-glucse are cnfrmers (b) epimers (c) anmers (d) enantimers JD Lee, lmns & Fryhle Fundamentals f Chemistry Textbk fr ass Cpyright 0 Wiley India Pvt Ltd All rights reserved

4 4 AI 008 (c) a -D () glucse and b -D () glucse differ nly at C; therefre, are anmers 9 tandard entrpies f X, Y and XY are 0, 40 and 50 J K ml, respectively Fr the reactin, X Y XY, =0kJ, t be at equilibrium, the temperature will be 50 K (b) 500 K (c) 750 K (d) 000 K (c) X Y XY = 0 kj r = 50 Jml 40 0 = 40 nce, G = T and at equilibrium G = 0, we have T = = 0 0 = 750 K 40 0 Fur species are listed belw (I) C (II) (III) 4 (IV) F Which ne f the fllwing is the crrect sequence f their acid strength? IV < II < III < I (b) II < III < I < IV (c) I < III < II < IV (d) III < I < IV < II (c) The rder is (IV) > (II) > (III) > (I) Weaker the cnjugate base, strnger is its cnjugate acid Which ne f the fllwing cnstitutes a grup f the iselectrnic species? C,, C,N (b) N, C, CN, N (c) CN, N,, C (d) N,, N, C (b) The number f electrns in each species is, N = 7 8 = 4, C = = 4, CN = 7 = 4 and N = 7 = 4 Which ne f the fllwing pairs f species have the same bnd rder? CN and N (b) CN and CN (c) and CN (d) N and CN CN and N has 4e each, hence same bnd rder = The inizatin enthalpy f hydrgen atm is 0 J ml - The energy required t excite the electrn in the atm frm n = t n = is J ml - (b) J ml - (c) J ml (d) J ml (d) Frm the relatin 0 = () Therefre, 0 and = ( ) 0 0 = = = Jml 5 4 Which ne f the fllwing is the crrect statement? Bric acid is a prtnic acid (b) Beryllium exhibits crdinatin number f six (c) Chlrides f bth beryllium and aluminium have bridged chlride structures in slid phase (d) B N is knwn as inrganic benzene (c) Al Al Be Be Be B N is called a inrganic benzene and bric acid is a Lewis acid 5 Given Cr =07 V, /Cr Fe =04 V The ptential /Fe fr the cell Cr Cr M Fe ( 0 ) ( 00 M) Fe is 0 V (b) 099 V (c) -09 V (d) -0 V Given Cr =07 V and /Cr Fe =04 V and /Fe the reactin is Cr Fe Fe Cr Accrding t Nernst equatin, Cr cell = cell lg [ ] n [ Fe ] = ( ) lg ( ) 0 ( 00 ) lg ( ) = 00 ( 00 ) = 00 lg = 00 lg0 lving, we get cell = 00 V Amunt f xalic acid present in a slutin can be determined by its titratin with KMn 4 slutin in the presence f 4 The titratin gives unsatisfactry result when carried ut in the presence f, because gets xidized by xalic acid t chlrine (b) furnishes ins in additin t thse frm xalic acid (c) reduces permanganate t Mn (d) xidizes xalic acid t carbn dixide and water (c) Mn 4 gets easily reduced t Mn in presence f, hence is nt used 7 The vapr pressure f water at 0 C is 75 mm g If 8 g f glucse (C ) is added t 78 g f water at 0 C, the vapr pressure f the resulting slutin will be JD Lee, lmns & Fryhle Fundamentals f Chemistry Textbk fr ass Cpyright 0 Wiley India Pvt Ltd All rights reserved

5 AI mm g (c) 500 mm g (d) Accrding t Rault s law p p = x p (b) 5750 mm g (d) 75 mm g slute 7 5 p p = p 0 p = 00 lving, we get p = 75 mm g 8 Amng the fllwing substituted silanes, the ne which will give rise t crss-linked silicne plymer n hydrlysis is R 4 (b) R (c) R (d) R R (b) Fr crss linking, we need mre than tw bnding sites ence, R R Cndensatin plymerizatin 9 In cntext with the industrial preparatin f hydrgen frm water gas (C ), which f the fllwing is the crrect statement? C and are fractinally separated using differences in their densities (b) C is remved by absrptin in aqueus Cu slutin (c) is remved thrugh cclusin with Pd (d) C is xidized t C with steam in the presence f a catalyst fllwed by absrptin f C in alkali (d) The reactin is C Water gas K C C (Acidic xide) K (base) 0 In a cmpund atms f element Y frm ccp lattice and thse f element X ccupy /rd f tetrahedral vids The frmula f the cmpund will be X 4 Y (b) X Y (c) X Y (d) X Y 4 The number f atms f Y = 4 (as ccp, hence rank = 4) The number f atms f X = ( / ) 8 (tetrahedral vids are duble the rank) ence, frmula f cmpund will be X 4 Y R n Gld numbers f prtective cllids A, B, C and D are 050, 00, 00 and 0005, respectively The crrect rder f their prtective pwers is D < A < C < B (b) C < B < D < A (c) A < C < B < D (d) B < D < A < C (c) The prtective pwer f lypphilic slutin is expressed in terms f gld number Lesser the gld number greater its prtective pwer The hydrcarbn which can react with sdium in liquid ammnia is C C C C CC C C (b) C C C C (c) C C = CC (d) C C C CC C (b) Terminal alkynes can frm acetylides because f acidic hydrgen The treatment f C MgX with C C C prduces C C = C (b) C C CC (c) C C = C C (d) C 4 (d) C MgX C C = C C 4 ence, C MgX acts as a base t abstract acidic hydrgen 4 The crrect decreasing rder f pririty fr the functinal grups f rganic cmpunds in the IUPAC system f nmenclature is C,, CN, C (b), C, CN, C (c) C, C,, CN (d) CN, C,, C 5 The pk a f a weak acid, A, is 480 The pk b f a weak base, B, is 478 The p f an aqueus slutin f the crrespnding salt, BA, will be 958 (b) 479 (c) 70 (d) 9 (c) The reactin is Nw since, BA B A A [ ] = B K K K w a Therefre, p = 70 b = 7 pk a pk b JD Lee, lmns & Fryhle Fundamentals f Chemistry Textbk fr ass Cpyright 0 Wiley India Pvt Ltd All rights reserved

6 JD Lee, lmns & Fryhle Fundamentals f Chemistry Textbk fr ass Cpyright 0 Wiley India Pvt Ltd All rights reserved