Practice Questions

Q52.For a given chemical reaction A →B at 300 K the free energy change is −49. 4 kJ mol−1 and the enthalpy of reaction is 51. 4 kJ mol−1. The entropy change of the reaction is _________ JK−1 mol−1. Q53. 4 g equimolar mixture of NaOH and Na2 CO3 contains xg of NaOH and yg of Na2 CO3. The value of x is g. (Nearest integer)

Q52.A proton and a Li3 + nucleus are accelerated by the same potential. If 𝜆Li and 𝜆p denote the de Broglie + 𝜆Li wavelengths of Li3 and proton respectively, then the value of is 𝑥× 10-1. The value of x 𝜆p is _____ (Rounded off to the nearest integer) [Mass of Li3 + = 8 . 3 mass of proton]

Q52.The number of photons emitted by a monochromatic (single frequency) infrared range finder of power 1 mW and wavelength of 1000 nm, in 0. 1 second is x × 1013 . The value of x is (Nearest integer) (h = 6. 63 × 10−34 Js, c = 3. 00 × 108 ms−1):

Q52.Number of electrons that Vanadium (Z = 23) has in p-orbitals is equal to:

Q52.The mole fraction of a solute in a 100 molal aqueous solution ________ ×10−2. (Round off to the Nearest Integer). [Given : Atomic masses: H : 1. 0 u, O : 16. 0 u ]

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.According to molecular orbital theory, the number of unpaired electron(s) in O22 - is _________ .

Q52.A ball weighing 10 g is moving with a velocity of 90 m s−1. If the uncertainty in its velocity is 5%, then the uncertainty in its position is _ ×10−33 m. (Rounded off to the nearest integer) [Given: h = 6. 63 × 10−34 Js]

Q52.For water Δvap H = 41 kJ mol−1 at 373 K and 1 bar pressure. Assuming that water vapour is an ideal gas that occupies a much larger volume than liquid water, the internal energy change during evaporation of water is (kJmol−1) : [ Use : R = 8. 3 J mol−1 K−1]

Q52.Complete combustion of 3 g of ethane gives x × 1022molecules of water. The value of x is ______ (Round off to the Nearest Integer). [Use : NA = 6. 023 × 1023; Atomic masses in u : C : 12. 0 ; O : 16. 0 ; H : 1. 0]

Q52.Five moles of an ideal gas at 293 K is expanded isothermally from an initial pressure of 2. 1 MPa to 1. 3 MPa against at constant external pressure 4. 3 MPa. The heat transferred in this process is ___ kJmol−1 . (Rounded-off to the nearest integer) [ Use R = 8. 314 J mol−1 K−1 ]

Q52.The number of chlorine atoms in 20 mL of chlorine gas at STP is _______ 1021 . (Round off to the Nearest Integer). [Assume chlorine is an ideal gas at STP R = 0. 083 L bar mol−1 K−1, NA = 6. 023 × 1023]

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

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

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

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.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.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 pH of a solution obtained by mixing 50 mL of 1 M HCl and 30 mL of 1 M NaOH is x × 10-4 . The value of x is (Nearest integer) log 2 . 5 = 0 . 3979

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

Q53.An average person needs about 10000 kJ energy per day. The amount of glucose (molar mass = 180. 0 g mol−1 ) needed to meet this energy requirement is ______ g. (Use : ΔCH (glucose) = −2700 kJ mol−1 ) Q54. 2 SO2( g) + O2( g) ⇌2 SO3( g) In an equilibrium mixture, the partial pressures are PSO3 = 43 kPa; PO2 = 530 Pa and PSO2 = 45 kPa. The equilibrium constant KP = _____ × 10−2. (Nearest integer) Q55. 250 mL of 0. 5M NaOH was added to 500 mL of 1M HCl. The number of unreacted HCl molecules in the solution after the complete reaction is p ×1021 . Find out p (Nearest integer) (NA = 6. 022 × 1023)

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.