Aieee chemistry -2008

AEEE –Past papers CHEMISTRY - UNSOLVED PAPER - 2008

SECTION – I Straight Objective Type This section contains multiple choice questions numbered 35 . Each question has 4 choices (A), (B), (C) and (D), out of which ONLY ONE is correct.

01 Problem The organic chloro compound, which shows complete stereochemical inversion during a SN2 reaction, is (C2H5)2CHCl (CH3)3CCl (CH3)2CHCl CH3Cl

Problem 02 Toluene is nitrated and the resulting product is reduced with tin and hydrochloric acid. The product so obtained is diazotised and then heated with cuprous bromide. The reaction mixture so formed contains mixture of o− and p−bromotoluenes mixture of o− and p−dibromobenzenes mixture of o− and p−bromoanilines mixture of o− and m−bromotoluenes

Problem 03 The coordination number and the oxidation state of the element ‘E’ in the complex [E(en)2(C2O4)]NO2 (where (en) is ethylene diamine) are, respectively, 6 and 2 4 and 2 4 and 3 6 and 3

Problem 04 Identify the wrong statements in the following: Chlorofluorocarbons are responsible for ozone layer depletion Greenhouse effect is responsible for global warming Ozone layer does not permit infrared radiation from the sun to reach the earth Acid rains is mostly because of oxides of nitrogen and sulphur

Problem 05 Phenol, when it first reacts with concentrated sulphuric acid and then with concentrated nitric acid, gives 2,4,6-trinitrobenzene o-nitrophenol p-nitrophenol nitrobenzene

Problem 06 In the following sequence of reactions, the alkene affords the compound ‘B’ O3 H2O 3 Zn CH 3 CH = CH 3 CH The compound B is CH3CH2CHO CH3COCH3 CH3CH2COCH3 CH3CHO

Problem 07 Larger number of oxidation states are exhibited by the actinoids than those by the lanthanoids, the main reason being 4f orbitals more diffused than the 5f orbitals lesser energy difference between 5f and 6d than between 4f and 5d orbitals more energy difference between 5f and 6d than between 4f and 5d orbitals more reactive nature of the actinoids than the lanthanoids

Problem 08 In which of the following octahedral complexes of Co (at. no. 27), will the magnitude of Δ o be the highest? [Co(CN)6]3− [Co(C2O4)3]3− [Co(H2O)6]3+ [Co(NH3)6]3+

Problem 09 At 80oC, the vapour pressure of pure liquid ‘A’ is 520 mm Hg and that of pure liquid ‘B’ is 1000 mm Hg. If a mixture solution of ‘A’ and ‘B’ boils at 80oC and 1 atm pressure, the amount of ‘A’ in the mixture is (1 atm = 760 mm Hg) 52 mol percent 34 mol percent 48 mol percent 50 mol percent

Problem 10 For a reaction ½ A 2B,-> rate of disappearance of ‘A’ is related to the rate of appearance of ‘B’ by the expression a. b. c. d.

Problem 11 The equilibrium constants P1 K and P2 K for the reactions X 2Y and Z P +Q, respectively are in the ratio of 1 : 9. If the degree of dissociation of X and Z be equal then the ratio of total pressure at these equilibria is 1 : 36 1 : 1 1 : 3 1 : 9

Problem 12 Oxidising power of chlorine in aqueous solution can be determined by the parameters indicated below: The energy involved in the conversion of (using the data, will be a. +152 kJmol−1 b. −610 kJmol−1 c. −850 kJmol−1 d. +120 kJmol−1

Problem 13 Which of the following factors is of no significance for roasting sulphide ores to the oxides and not subjecting the sulphide ores to carbon reduction directly? Metal sulphides are thermodynamically more stable than CS2 CO2 is thermodynamically more stable than CS2 Metal sulphides are less stable than the corresponding oxides CO2 is more volatile than CS2

Problem 14 Bakelite is obtained from phenol by reacting with (CH2OH)2 CH3CHO CH3COCH3 HCHO

Problem 15 For the following three reactions a, b and c, equilibrium constants are given: a. CO (g ) +H 2O (g) CO 2(g) +H2 (g) ; K1 b. CH4 (g) +H2O (g) CO2 (g) + 3H 2(g) ; K2 c. CH4 (g) + 2H2 O (g) CO2 (g) + 4H2 (g) ; K4 Which of the following relations is correct? K1 √2 = K3 K2 K3 = K1 K3 = K1K2 K3K32=k21

Problem 16 The absolute configuration of is S, S R, R R, S S, R

Problem 17 The electrophile, E⊕ attacks the benzene ring to generate the intermediate σ-complex. Of the following, which σ-complex is of lowest energy? a. b. c. d.

Problem 18 α-D-(+)-glucose and β-D-(+)-glucose are Conformers epimers anomers enantiomers

Problem 19 Standard entropy of X2, Y2 and XY3 are 60, 40 and 50 JK−1mol−1, respectively. For the reaction, ½ X2 + 3/2 Y3-> X Y3,∆ H = - to be at equilibrium, the perature will be 1250 K 500 K 750 K 1000 K

Problem 20 Four species are listed below HCO−3 H3O+ iii. HSO−4 iv. HSO3F Which one of the following is the correct sequence of their acid strength? iv < ii < iii < I ii < iii < i < iv i < iii < ii < iv iii < i < iv < ii

Problem 21 Which one of the following constitutes a group of the isoelectronic species? C 22 − , O2 − , CO, NO NO+ , C22 − , CN− , N 2 CN− , N2 , O22 − , C 22 − N 2 , O 2− , NO+ , CO

Problem 22 Which one of the following pairs of species have the same bond order? CN− and NO+ CN− and CN+ 2 O− and CN− NO+ and CN+

Problem 23 The ionization enthalpy of hydrogen atom is 1.312 × 106 Jmol−1. The energy required to excite the electron in the atom from n = 1 to n = 2 is 8.51 × 105 Jmol−1 6.56 × 105 Jmol−1 7.56 × 105 Jmol−1 9.84 × 105 Jmol−1

Problem 24 Which one of the following is the correct statement? Boric acid is a protonic acid Beryllium exhibits coordination number of six Chlorides of both beryllium and aluminium have bridged chloride structures in solid phase B2H6.2NH3 is known as ‘inorganic benzene’

Problem 25 Given The potential for the Fe is 0.26 V 0.399 V −0.339 V −0.26 V

Problem 26 Amount of oxalic acid present in a solution can be determined by its titration with KMnO4 solution in the presence of H2SO4. The titration gives unsatisfactory result when carried out in the presence of HCl, because HCl gets oxidised by oxalic acid to chlorine furnishes H+ ions in addition to those from oxalic acid reduces permanganate to Mn2+ oxidises oxalic acid to carbon dioxide and water

Problem 27 The vapour pressure of water at 20oC is 17.5 mm Hg. If 18 g of glucose (C6H12O6) is added to 178.2 g of water at 20oC, the vapour pressure of the resulting solution will be 17.675 mm Hg 15.750 mm Hg 16.500 mm Hg 17.325 mm Hg

Problem 28 Among the following substituted silanes the one which will give rise to cross linked silicone polymer on hydrolysis is R4Si RSiCl3 R2SiCl2 R3SiCl

Problem 29 In context with the industrial preparation of hydrogen from water gas (CO + H2), which of the following is the correct statement? CO and H2 are fractionally separated using differences in their densities CO is removed by absorption in aqueous Cu2Cl2 solution H2 is removed through occlusion with Pd CO is oxidised to CO2 with steam in the presence of a catalyst followed by absorption of CO2 in alkali

Problem 30 In a compound atoms of element Y from ccp lattice and those of element X occupy 2/3rd of tetrahedral voids. The formula of the compound will be X4Y3 X2Y3 X2Y X3 Y4

Problem 31 Gold numbers of protective colloids A, B, C and D are 0.50, 0.01, 0.10 and 0.005, respectively. The correct order of their protective powers is D < A < C < B C < B < D < A A < C < B < D B < D < A < C

Problem 32 The hydrocarbon which can react with sodium in liquid ammonia is CH3CH2CH2C≡CCH2CH2CH3 CH3CH2C≡CH CH3CH=CHCH3 CH3CH2C≡CCH2C

Problem 33 The treatment of CH3MgX with CH3C≡C−H produces CH3−CH=CH2 CH3C≡C−CH3 c. CH4

Problem 34 The correct decreasing order of priority for the functional groups of organic compounds in the IUPAC system of nomenclature is −COOH, −SO3H, −CONH2, −CHO −SO3H, −COOH, −CONH2, −CHO −CHO, −COOH, −SO3H, −CONH2 −CONH2, −CHO, −SO3H, −COOH

Problem 35 The pKa of a weak acid, HA, is 4.80. The pKb of a weak base, BOH, is 4.78. The pH of an aqueous solution of the corresponding salt, BA, will be 9.58 4.79 7.01 9.22

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Aieee chemistry -2008

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