Practice Questions

Q33.Which of the following presents the correct order of second ionization enthalpies of C, N, O and F ? (1) F > O > N > C (2) O > N > F > C (3) C > N > O > F (4) O > F > N > C

Q33.The limiting line in Balmer series will have a frequency of (Rydberg constant, R∞= 3.29 × 1015 cycles /s ) (1) 8.22 × 1014 s−1 (2) 3.29 × 1015 s−1 (3) 3.65 × 1014 s−1 (4) 5.26 × 1013 s−1

Q33.If the radius of first orbit of H atom is a0 , the deBroglie wavelength of an electron in the third orbit is (1) 4πa0 (2) 8πa0 (3) 6πa0 (4) 2πa0

Q34.Among the following species which two have trigonal pyramidal shape? (I) NI3 (II) I−3 (III) SO2−3 (IV) NO−3 (1) I and III (2) III and IV (3) I and IV (4) II and III

Q34.The molecule having smallest bond angle is : (1) NCl3 (2) AsCl3 (3) SbCl3 (4) PCl3

Q34.Which pair of elements with the given atomic numbers is expected to have similar properties? (1) 40,72 (2) 20,36 (3) 10,28 (4) 11,12

Q35.Dipole moment is shown by (1) 1,2-dichlorobenzene (2) trans 2, 3-dichloro-2-butene (3) 1,4-chlorobenzene (4) trans-1,2-dinitroethene

Q35.In which of the following pairs the two species are not isostructural? (1) CO2−3 and NO−3 (2) PCl+4 and SiCl4 (3) PF5 and BrF5 (4) AlF3−6 and SF6

Q35.The formation of molecular complex BF3 −NH3 results in a change in hybridization of boron (1) from sp2 to dsp2 (2) from sp2 to sp3 (3) from sp3 to sp2 (4) from sp3 to sp3d

Q35.Among the following, the species having the smallest bond is (1) NO− (2) NO+ (3) O2 (4) NO

Q36.The compressibility factor for a real gas at high pressure is : (1) 1 + RT/pb (2) 1 (3) 1 + pb/RT (4) 1 −pb/RT

Q36.Although CN− ion and N2 molecule are isoelectronic, yet N2 molecule is chemically inert because of (1) presence of more number of electrons in bonding (2) lone bond energy orbitals (3) absence of bond polarity (4) uneven electron distribution.

Q36.Among the following, the molecule with the lowest dipole moment is (1) CHCl3 (2) CH3Cl (3) CH2Cl2 (4) CCl4

Q37.One mole of an ideal gas is expanded isothermally and reversibly to half of its initial pressure. ΔS for the process in JK−1 mol−1 is [ln 2 = 0.693 and R = 8.314, J/(molK)] (1) 6.76 (2) 5.76 (3) 10.76 (4) 8.03

Q37.Among the following chloro-compound having the lowest dipole moment is (1) (2) (3) (4) Q38. α, v and u represent most probable velocity, average velocity and root mean square velocity respectively of a gas at a particular temperature. The correct order among the following is (1) u > v > α (2) v > u > α (3) α > u > v (4) u > α > v

Q37.The incorrect expression among the following is : (1) ΔGsystem = −T (2) In isothermal process wreversible = −nRT ln Vf ΔStotal Vi (3) ln K = ΔH0−TΔS0RT (4) K = e−ΔG0/RT

Q37.Which of the following has the square planar structure? (1) XeF4 (2) NH+4 (3) BF−4 (4) CCl4

Q38.One mole of O2( g) and two moles of SO2( g) were heated in a closed vessel of one-litre capacity at 1098 K. At equilibrium 1.6 moles of SO3( g) were found. The equilibrium constant Kc of the reaction would be (1) 30 (2) 40 (3) 80 (4) 60

Q38.The compound of xenon with zero dipole moment is (1) XeO3 (2) XeF4 (3) XeOF4 (4) XeO2

Q39.The pH of a 0.1 molar solution of the acid HQ is 3 . The value of the ionization constant, Ka of this acid is : (1) 3 × 10−1 (2) 1 × 10−3 (3) 1 × 10−5 (4) 1 × 10−7

Q39.The electron affinity of chlorine is 3.7eV.1 gram of chlorine is completely converted to Cl− ion in a gaseous state. (1eV = 23.06kcalmol−1). Energy released in the process is (1) 4.8kcal (2) 7.2kcal (3) 8.2kcal (4) 2.4kcal

Q39.The solubility of PbI2 at 25∘C is 0.7 g L−1 . The solubility product of PbI2 at this temperature is (molar mass of PbI2 = 461.2 g mol−1 ) (1) 1.40 × 10−9 (2) 0.14 × 10−9 (3) 140 × 10−9 (4) 14.0 × 10−9

Q39.The difference between the reaction enthalpy change (ΔrH) and reaction internal energy change (ΔrU) for the reaction: 2C6H6(l) + 15O2( g) ⟶ at 300 K is (R = 8.314 J mol−1 K−1) JEE Main 2012 (12 May Online) JEE Main Previous Year Paper (1) 0 J mol−1 (2) 2490 J mol−1 (3) −2490 J mol−1 (4) −7482 J mol−1 Q40. 8 mol of AB3( g) are introduced into a 1.0dm3 vessel. If it dissociates as 2AB3(g) ⇌A2(g) + 3B2(g). At equilibrium, 2 mol of A2 are found to be present. The equilibrium constant of this reaction is (1) 2 (2) 3 (3) 27 (4) 36

Q39.An open vessel at 300 K is heated till 2/5th of the air in it is expelled. Assuming that the volume of the vessel remains constant, the temperature to which the vessel is heated, is (1) 1500 K (2) 400 K (3) 500 K (4) 750 K

Q40.The solubility (in mol L−1 ) of AgCl (Ksp = 1.0 × 10−10) in a 0.1MKCl solution will be (1) 1.0 × 10−9 (2) 1.0 × 10−10 (3) 1.0 × 10−5 (4) 1.0 × 10−11