Practice Questions

Q35.After understanding the assertion and reason, choose the correct option. Assertion: In the bonding molecular orbital (MO) of H2, electron density is increased between the nuclei. Reason: The bonding MO is ψA + ψB , which shows destructive interference of the combining electron waves. (1) Assertion and Reason are correct, but Reason is (2) Assertion and Reason are correct and Reason is not the correct explanation for the Assertion. the correct explanation for the Assertion. (3) Assertion is incorrect, Reason is correct. (4) Assertion is correct, Reason is incorrect.

Q35.The following reaction is performed at 298 K. 2NO(g) + O2(g) ⇌2NO2(g) The standard free energy of the formation of NO(g) is 86. 6 kJ mol−1 at 298 K. What is the standard free energy of the formation of NO2(g) at 298 K? (KP = 1.6 × 1012) (1) 0.5[2 × 86,600 −R(298) ln (1.6 × 1012)] (2) R(298) ln(1.6 × 1012)−86,600 (3) 86,600 + R(298) ln (1.6 × 1012) (4) 86,600 − ln(1.6×1012)R(298)

Q36.Which compounds exhibits maximum dipole moment among the following? JEE Main 2015 (11 Apr Online) JEE Main Previous Year Paper (1) (2) (3) (4)

Q36.The standard Gibbs energy change at 300 K for the reaction 2A ⇌B + C is 2494.2 J. At a given time, the composition of the reaction mixture is [A] = 21 , [B] = 2 and [C] = 12 . The reaction proceeds in the: [R = 8.314 J/K −mol , e = 2.718 ] {Given antilog (-0.44)=0.36} (1) Reverse direction because Q < KC (2) Forward direction because Q > KC (3) Reverse direction because Q > KC (4) Forward direction because Q < KC

Q38.Gaseous N2O4 dissociates into gaseous NO2 according to the reaction N2O4(g) ⇌2NO2(g) At 300 K and 1 atm pressure, the degree of dissociation of N2O4 is 0. 2 . If one mole of N2O4 gas is contained in a vessel, then the density of the equilibrium mixture is : (1) 3. 11 g/L (2) 1. 56 g/L (3) 4. 56 g/L (4) 6. 22 g/L

Q38.Which one of the following alkaline earth metal sulphates has its hydration enthalpy greater than its lattice enthalpy? (1) SrSO4 (2) CaSO4 (3) BeSO4 (4) BaSO4 JEE Main 2015 (04 Apr) JEE Main Previous Year Paper

Q38.The increase of pressure on ice ⇌water system at constant temperature will lead to: (1) A decrease in the entropy of the system (2) An increase in the Gibbs energy of the system (3) A shift of the equilibrium in the forward direction(4) No effect on the equilibrium

Q39.In Carius method of estimation of halogens, 250 mg of an organic compound gave 141 mg AgBr. What is the percentage of bromine in the compound (atomic mass of Ag = 108 and atomic number of Br = 80 )? (1) 60 (2) 24 (3) 36 (4) 48

Q40.Which of the following compounds will exhibit geometrical isomerism? (1) 1, 1 - Diphenyl - 1 - propane (2) 1 - Phenyl - 2 - butene (3) 3 - Phenyl - 1 - butene (4) 2 - Phenyl - 1 - butene

Q40.The correct order of thermal stability of hydroxides is (1) Mg(OH)2 < Sr(OH)2 < Ca(OH)2 < Ba(OH)2 (2) Mg(OH)2 < Ca(OH)2 < Sr(OH)2 < Ba(OH)2 (3) Ba(OH)2 < Sr(OH)2 < Ca(OH)2 < Mg(OH)2 (4) Ba(OH)2 < Ca(OH)2 < Sr(OH)2 < Mg(OH)2 JEE Main 2015 (10 Apr Online) JEE Main Previous Year Paper Q41.1.4 g of an organic compound was digested according to Kjeldahl's method and the ammonia evolved was absorbed in 60 mL of M/10 H2SO4 solution. The excess sulphuric acid required 20 mL of M/10 NaOH solution for neutralization. The percentage of nitrogen in the compound is: (1) 24 (2) 3 (3) 5 (4) 10

Q41.The number of structural isomers for C6H14 is: (1) 4 (2) 5 (3) 6 (4) 3

Q42.Match the organic compounds in column - I with the Lassaigne's test result in column - II appropriately: Column – I Column - II A. Aniline i. Red colour with FeCl3 B. Benzene sulfonic acid ii. Violet color with sodium nitroprusside C. Thiourea iii. Blue color with and acidic solution of FeSO4 (1) A - ii ; B - iii ; C - i (2) A - iii ; B - ii ; C - i (3) A - ii ; B - i ; C - iii (4) A - iii ; B - i ; C - ii

Q42.The optically inactive compound from the following is: (1) 2-chloropropanal (2) 2-chloro-2-methylbutane (3) 2-chlorobutane (4) 2-chloropentane

Q43.A compound A with molecular formula C10H13Cl, gives a white precipitate on adding silver nitrate solution. A on reacting with alcoholic KOH gives compound B as the main product. B on ozonolysis, gives C and D. C gives Cannizaro reaction, but not aldol condensation. D gives aldol condensation, but not Cannizaro reaction. A is (1) (2) (3) (4)

Q43.The vapour pressure of acetone at 20oC is 185 torr. When 1. 2 g of a non-volatile substance was dissolved in 100 g of acetone at 20oC , its vapour pressure was 183 torr. The molar mass (g mol−1) of the substance is: (1) 488 (2) 32 (3) 64 (4) 128

Q45.Determination of the molar mass of acetic acid in benzene using freezing point depression is affected by: (1) Complex formation (2) Association (3) Partial ionization (4) Dissociation

Q46.A variable, the opposite external potential (Eext) is applied to the cell Zn Zn2+ (1M) ∥Cu2+ (1 M) Cu, of potential 1. 1 V. When Eext < 1.1 V and Eext > 1.1 V, respectively electrons flow from (1) anode to cathode in both the cases. (2) anode to cathode and cathode to anode. (3) cathode to anode and anode to cathode. (4) cathode to anode in both cases.

Q46.At 298 K, the standard reduction potentials are 1. 51 V for MnO−4 Mn2+ , 1. 36 V for Cl2|Cl−1., 07 V for Br2|Br−0., 54 V for I2|I− . At pH = 3, permanganate is expected to oxidize: ( RTF = 0.059) (1) Cl− and Br− (2) Br− and I− (3) I− only (4) Cl− , Br− and I−

Q47.The reaction 2N2O5(g) →4NO2(g) + O2(g) follows first order kinetics. The pressure of a vessel containing only N2O5 was found to increase from 50 mm Hg to 87.5 mm Hg in 30 min. The pressure exerted by the gases after 60 min. Will be (Assume temperature remains constant) : (1) 106.25 mm Hg (2) 125 mm Hg (3) 116.25 mm Hg (4) 150 mm Hg

Q47.In the context of the Hall-Heroult process for the extraction of Al, which of the following statements is false? (1) Na3AlF6 serves as the electrolyte. (2) CO and CO2 are produced in this process. (3) Al2O3 is mixed with CaF2 which lowers the (4) Al3+ is reduced at the cathode to form Al. melting point of the mixture and brings conductivity.

Q48.For the equilibrium, A(g) ⇌B(g), Δ H is −40 kJ / mol . If the ratio of the activation energies of the forward (Ef) and reverse (Eb) reactions is 32 then: (1) Ef = 30 kJ / mol, Eb = 70 kJ / mol (2) Ef = 70 kJ / mol, Eb = 30 kJ / mol (3) Ef = 80 kJ / mol, Eb = 120 kJ / mol (4) Ef = 60 kJ / mol, Eb = 100 kJ / mol

Q49.Under ambient conditions, which among the following surfactants will form micelles in aqueous solution at lowest molar concentration? ⊕ (1) Br_ (2) CH3 −(CH2)13 −OSO−3 Na+ CH3 (CH2)11 N(CH3)3 ⊕ (3) ⊝ (4) CH3 —(CH2)8— COO⊝Na+ Br CH3 (CH2)15 N(CH3)3

Q50.Match the catalysts to the correct process. Catalyst Process A. TiCl3 i. Wacker process B. PdCl2 ii. Ziegler – Natta polymerisation C. CuCl2 iii. Contact process` D. V2O5 iv. Deacon’s process (1) A →iii , B →i , C →ii , D →iv (2) A →iii , B →ii , C →iv , D →i (3) A →ii , B →i , C →iv , D →iii (4) A →ii , B →iii , C →iv , D →i

Q50.The least number of oxyacids are formed by: (1) Chlorine (2) Fluorine (3) Sulphur (4) Nitrogen

Q51.The cation that will not be precipitated by H2S in the presence of dil HCl is: (1) Co2+ (2) As3+ (3) Pb2+ (4) Cu2+