Practice Questions

Q52.The number of lone pairs of electrons on the central I atom in I−3 is JEE Main 2021 (20 Jul Shift 1) JEE Main Previous Year Paper

Q52.The reaction of cyanamide, NH2 CN(s) with oxygen was run in a bomb calorimeter and ΔU was found to be −742. 24 kJ mol−1 . The magnitude of ΔH298 for the reaction NH2 CN(s) + 23 O2(g) →N2(g) + O2(g) + H2O(l) is kJ . (Rounded off to the nearest integer) [Assume ideal gases and R = 8. 314 J mol−1 K−1 ]

Q52.According to the following figure, the magnitude of the enthalpy change of the reaction A + B →M + N in kJ mol−1 is equal to __________ . (Integer answer)

Q52. AB3 is an interhalogen T-shaped molecule. The number of lone pairs of electrons on A is (Integer answer)

Q53.Consider the reaction N2O4( g) ⇌2 NO2( g) The temperature at which KC = 20. 4 and KP = 600. 1, is ______ K. (Round off to the Nearest Integer). [Assume all gases are ideal and R = 0. 0831 L bar K−1 mol−1]

Q53.At 25°C, 50 g of iron reacts with HCl to form FeCl2 . The evolved hydrogen gas expands against a constant pressure of 1 bar. The work done by the gas during this expansion is -_______ J. (Round off to the Nearest Integer) [Given : R = 8. 314 J mol−1 K−1 . Assume, hydrogen is an ideal gas] JEE Main 2021 (16 Mar Shift 2) JEE Main Previous Year Paper [Atomic mass off Fe is 55. 85 u ]

Q53.The average S −F bond energy in kJ mol−1 of SF6 is _. (Rounded off to the nearest integer) [Given : The values of standard enthalpy of formation of SF6(g), S(g) and F(g) are −1100, 275 and 80 kJ mol−1 respectively.]

Q53.When light of wavelength 248 nm falls on a metal of threshold energy 3. 0 eV , the de-Broglie wavelength of o emitted electrons is ________ A . (Round off to the Nearest Integer). [Use : √3 = 1. 73, h = 6. 63 × 10−34 Js; me = 9. 1 × 10−31 kg; c = 3. 0 × 108 ms−1; 1 eV = 1. 6 × 10−19 J]

Q53.The difference between bond orders of CO and NO⊕ is x2 where x = (Round off to the Nearest Integer)

Q53.When 400 mL of 0. 2 M H2 SO4 solution is mixed with 600 mL of 0. 1 MNaOH solution, the increase in temperature of the final solution is — × 10−2 K . (Round off to the nearest integer). [Use : H+(aq) + OH−(aq) →H2O :ΔγH = −57. 1 kJ mol−1] Specific heat of H2O = 4. 18 J K−1 g−1 , density of H2O = 1. 0 g cm−3 Assume no change in volume of solution on mixing.

Q53.The volume occupied by 4. 75 g of acetylene gas at 50°C and 740 mm Hg pressure is ____________ L. (Rounded off to the nearest integer) [Given R = 0. 0826 L atm K−1 mol−1 ]

Q53.For the reaction A𝑔→Bg, the value of the equilibrium constant at 300 K and 1 atm is equal to 100 . 0 . The value of ΔGo for the reaction at 300 K and 1 atm in Jmol-1 is -𝑥R, where x is (Rounded off to the nearest integer) R = 8 . 31 J mol-1 K-1 and ln10 = 2 . 3

Q53.The number of species having non-pyramidal shape among the following is: (A) SO3 (B) NO−3 (C) PCl3 (D) CO2−3

Q53. AX is a covalent diatomic molecule where A and X are second row elements of periodic table. Based on Molecular orbital theory, the bond order of AX is 2. 5. The total number of electrons in AX is_____. (Round off to the Nearest Integer).

Q53.The ionization enthalpy of Na+ formation from Na(g) is 495. 8 kJ mol−1, while the electron gain enthalpy of Br is −325. 0 kJ mol−1 . Given the lattice enthalpy of NaBr is −728. 4 kJ mol −1 . The energy for the formation of NaBr ionic solid is (−)_____10−1 kJ mol−1 Q54. 0. 4 g mixture of NaOH, Na2 CO3 and some inert impurities was first titrated with 10N HCl using phenolphthalein as an indicator, 17. 5 mL of HCl was required at the end point. After this methyl orange was added and titrated. 1. 5 mL of same HCl was required for the next end point. The weight percentage of Na2 CO3 in the mixture is (Rounded-off to the nearest integer)

Q53.Consider titration of NaOH solution versus 1. 25 M oxalic acid solution. At the end point following burette readings were obtained. (i) 4. 5 mL (ii) 4. 5 mL (iii) 4. 4 mL (iv) 4. 4 mL (v) 4. 4 mL If the volume of oxalic acid taken was 10. 0 mL then the molarity of the NaOH solution is ___ M. (Rounded- off to the nearest integer)

Q53.The Born-Haber cycle for KCl is evaluated with the following data: ΔfHΘ for KCl = −436.7 kJmol−1; ΔsubHΘ for K = 89.2 kJmol−1; Δionization HΘ for K = 419.0 kJ mol −1; Δelectron gain HΘ for Cl(g) = −348.6 kJmol−1 Δbond HΘ for Cl2 = 243.0 kJmol−1 The magnitude of lattice enthalpy of KCl in kJmol−1 is (Nearest integer)

Q53. A3B2 is a sparingly soluble salt of molar mass M(g mol−1) and solubility x g L−1. The solubility product The value of a is __________ . (Integer answer) satisfies Ksp = a( Mx ) 5.

Q53.The gas phase reaction 2 A(g) ⇌A2(g) at 400 K has ΔGo = +25. 2 kJ mol−1 . The equilibrium constant KC for this reaction is ___ ×10−2 . (Round off to the Nearest integer) Use : R = 8. 3 J mol−1 K−1, ln 10 = 2. 3 log10 2 = 0. 30, 1 atm = 1 bar antilog (−0. 3) = 0. 501

Q53.An LPG cylinder contains gas at a pressure of 300 kPa at 27°C. The cylinder can withstand the pressure of 1. 2 × 106 Pa . The room in which the cylinder is kept catches fire. The minimum temperature at which the bursting of cylinder will take place is __________ ∘C. (Nearest integer)

Q53.If the standard molar enthalpy change for combustion of graphite powder is −2. 48 × 102 kJ mol−1 , the amount of heat generated on combustion of 1 g of graphite powder in kJ (Nearest integer):

Q53.For a chemical reaction A + B = C + D (ΔrHΘ = 80 kJ mol−1) the entropy change ΔrSΘ depends on the temperature T (in K) as ΔrSΘ = 2T(JK−1 mol−1) . Minimum temperature at which it will become spontaneous is K. (Integer)

Q53.The equilibrium constant Kc at 298 K for the reaction A + B ⇌C + D is 100 . Starting with an equimolar solution with concentrations of A, B, C and D all equal to 1M, the equilibrium concentration of D is _____ ×10−2M. (Nearest integer)

Q53.The spin-only magnetic moment value of B2+ species is × 10-2BM (Nearest integer) [ Given : √3 = 1 . 73]

Q53.The number of f electrons in the ground state electronic configuration of Np(Z = 93) is ______ .(Integer answer)