Practice Questions

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

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

Q53.A home owner uses 4 . 00 × 103 m3 of methane CH4 gas, (assume CH4 is an ideal gas) in a year to heat his home. Under the pressure of 1 . 0 atm and 300 K, mass of gas used is x × 105 g. The value of x is ______. (Nearest integer) (Given R = 0 . 083 L atm K-1 mol-1)

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.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]

Q54.The number of hydrogen bonded water molecule(s) associated with stoichiometry CuSO4 ⋅5H2O is __________ .

Q54.The pH of ammonium phosphate solution, if pka of phosphoric acid and pkb of ammonium hydroxide are 5. 23 and 4. 75 respectively, is

Q54.For water at 100°C and 1 bar, Δvap H −Δvap U =¯× 102 J mol−1 (Round off to the Nearest Integer) [Use : R = 8. 31 J mol−1 K−1] [Assume volume of H2O(l) is much smaller than volume of H2O(g). Assume H2O(g) treated as an ideal gas]

Q54.A homogeneous ideal gaseous reaction AB2(g) ⇌A(g) + 2 B(g) is carried out in a 25 litre flask at 27°C . The initial amount of AB2 was 1 mole and the equilibrium pressure was 1. 9 atm . The value of Kp is x × 10−2 . The value of x is (Integer answer) [R = 0. 08206 dm3 atm K−1 mol−1]

Q54.The pressure exerted by a non-reactive gaseous mixture of 6. 4 g of methane and 8. 8 g of carbon dioxide in a 10 L vessel at 27°C is _____ kPa. (Round off to the Nearest Integer). [Assume gases are ideal, R = 8. 314 J mol−1 K−1 Atomic masses: C : 12. 0 u, H : 1. 0 u, O : 16. 0 u ]

Q54.In the sulphur estimation, 0. 471 g of an organic compound gave 1. 44 g of barium sulfate. The percentage of sulphur in the compound is. (Nearest integer) (Atomic Mass of Ba = 137u )

Q54.At 298 K, the enthalpy of fusion of a solid X is 2 . 8 kJ mol-1 and the enthalpy of vaporisation of the liquid X is 98 . 2 kJ mol-1. The enthalpy of sublimation of the substance X in kJ mol-1 is ______. (in nearest integer)

Q54.The OH− concentration in a mixture of 5. 0 mL of 0. 0504 M NH4 Cl and 2 mL of 0. 0210 M NH3 solution is x × 10−6 M . The value of x is (Nearest integer) [Given Kw = 1 × 10−14 and Kb = 1. 8 × 10−5]

Q54.When 0. 15 g of an organic compound was analyzed using Carius method for estimation of bromine, 0. 2397 g of AgBr was obtained. The percentage of bromine in the organic compound is _________.(Nearest integer) [Atomic mass : Silver = 108, Bromine = 80]

Q54.The stepwise formation of CuNH34 2 + is given below: K1 Cu2 + + NH3 ⇌CuNH3 2 + K2 CuNH3 2 + + NH3 ⇌CuNH32 2 + K3 CuNH32 2 + + NH3 ⇌CuNH33 2 + K4 CuNH33 2 + + NH3 ⇌CuNH34 2 + The value of stability constants K1, K2, K3 and K4 are 104, 1 . 58 × 103, 5 × 102 and 102 respectively. The overall equilibrium constants for dissociation of CuNH34 2 + is 𝑥× 10-12 . The value of x is _____ (Rounded off to the nearest integer)

Q54.A system does 200 J of work and at the same time absorbs 150 J of heat. The magnitude of the change in internal energy is ______ J. (Nearest integer)

Q54.Assuming ideal behaviour, the magnitude of log K for the following reaction at 25°C is x × 10−1. The value of x is __________. (Integer answer) 3HC ≡CH(g) ⇌C6H6(l) [Given: ΔfG°(HC ≡CH) = −2. 04 × 105 J mol−1; ΔfG°(C6H6) = −1. 24 × 105 J mol−1; R = 8. 314 J K−1 mol−1 ]

Q54.The equilibrium constant for the reaction A(s) ⇌M(s) + 12 O2( g) is Kp = 4. At equilibrium, the partial pressure of O2 is _____ atm. (Round off to the nearest integer) Q55. 10. 0 mL of 0. 05 M KMnO4 solution was consumed in a titration with 10. 0 mL of given oxalic acid dihydrate solution. The strength of given oxalic acid solution is ........ ×10−2 g/L . (Round off to the nearest integer)

Q54.Sulphurous acid (H2 SO3) has Ka1 = 1. 7 × 10−2 and Ka2 = 6. 4 × 10−8. The pH of 0. 588 M H2 SO3 is____________ (Round off to the Nearest Integer ).

Q54.For the reaction A(g) ⇌B(g) at 495 K, ΔrG° = −9. 478 kJ mol−1 If we start the reaction in a closed container at 495 K with 22 millimoles of A , the amount of B is the equilibrium mixture is ________ millimoles. (Round off to the Nearest Integer). [R = 8. 314 J mol−1 K−1; ℓn10 = 2. 303] JEE Main 2021 (16 Mar Shift 1) JEE Main Previous Year Paper