Practice Questions

Q35.The standard reaction Gibbs energy for a chemical reaction at an absolute temperature T is given by ΔG∘= A −BT where A and B are non-zero constants. Which of the following is true about this reaction? (1) Exothermic if B < 0 (2) Endothermic if A > 0 (3) Endothermic if A < 0 and B > 0 (4) Exothermic if A > 0 and B < 0

Q35.In which one of the following equilibria, Kp ≠Kc? (1) 2HI(g) ⇌H2(g) + I2(g) (2) 2C(s) + O2(g) ⇌2CO(g) (3) 2NO(g) ⇌N2(g) + O2(g) (4) NO2(g) + SO2(g) ⇌NO(g) + SO3(g)

Q36.In an acid-base titration, 0.1 M HCl solution was added to the NaOH solution of unknown strength. Which of the following correctly shown the change of pH of the titration mixture in this experiment? JEE Main 2019 (09 Apr Shift 2) JEE Main Previous Year Paper (1) A (2) B (3) D (4) C

Q36.In the reaction of oxalate with permanganate in acidic medium, the number of electrons involved in producing one molecule of CO2 is: (1) 2 (2) 10 (3) 1 (4) 5

Q36.Consider the reaction N2( g) + 3H2( g) ⇌2NH3( g) The equilibrium constant of the above reaction is KP . If pure ammonia is left to dissociate, the partial pressure of ammonia at equilibrium is given by (Assume that PNH3 << Ptotal at equilibrium) (1) 33/2 K1/2P P2 (2) K1/2P2P 16 16 (3) K1/2P2P (4) 33/2 K1/2P P2 4 4

Q36.An open vessel at 27oC is heated until two fifth of the air (assumed as an ideal gas) in it has escaped from the vessel. Assuming that the volume of the vessel remains constant, the temperature to which the vessel has heated is: (1) 750oC (2) 500oC (3) 750K (4) 500K

Q36.In a chemical reaction, A + 2B ⇌2CK + D , the initial concentration of B was 1.5 times of the concentration of A , but the equilibrium concentrations of A and B were found to be equal. The equilibrium constant (K) for the chemical reaction is: (1) 1 (2) 4 (3) 1 (4) 16 4

Q36.For the reaction, 2SO2g + O2g ⇌2SO3g, ∆H = - 57.2 kJ mol-1 and Kc = 1.7 × 1016 . Which of the following statements is incorrect? (1) The equilibrium constant is large suggestive of (2) The equilibrium will shift in forward direction as reaction going to completion and so, no catalyst the pressure increases. is required. (3) The equilibrium constant decreases as the (4) The addition of inert gas at constant volume will temperature increases. not affect the equilibrium constant.

Q36.Enthalpy of sublimation of iodine is 24 cal g-1 at 200°C . If specific heat of I2 (s) and I2 (vap) are 0.055 and 0.031 cal g-1K-1 respectively, then enthalpy of sublimation of iodine at 250°C in cal g-1 is: (1) 11.4 (2) 2.85 (3) 22.8 (4) 5.7

Q36.For the equilibrium 2H2O ⇌H3O+ + OH−; the value of ΔG∘ at 298 K is approximately: (1) 100 kJ mol−1 (2) −80 kJ mol−1 (3) 80 kJ mol−1 (4) −100 kJ mol−1

Q37.The number of 2 -centre- 2 -electron and 3 -centre- 2 -electron bonds in B2H6 , respectively, are: (1) 4 and 2 (2) 2 and 4 (3) 2 and 2 (4) 2 and 1 JEE Main 2019 (10 Jan Shift 2) JEE Main Previous Year Paper

Q37.The pH of a 0.02 M NH4Cl solution will be [Given: KbNH4OH = 10-5 and log⁡2 = 0.301] (1) 4.65 (2) 2.65 (3) 4.35 (4) 5.35

Q37.The chemical nature of hydrogen peroxide is: (1) Oxidizing and reducing agent in both acidic and (2) Oxidizing agent in acidic medium, but not in basic medium. basic medium (3) Oxidizing and reducing agent in acidic medium, (4) Reducing agent in basic medium, but not in but not in basic medium acidic medium.

Q37.What is the molar solubility of AIOH3 in 0.2 M NaOH solution? Given that, solubility product of AlOH3 = 2.4 × 10-24 : (1) 3 × 10-19 (2) 12 × 10-21 (3) 12 × 10-23 (4) 3 × 10-22

Q37.The structures of beryllium chloride in the solid state and vapour phase, respectively, are: (1) chain and chain (2) dimeric and chain (3) chain and dimeric (4) dimeric and dimeric

Q37.Match the following items in column I with the corresponding items in column II. (1) (i) → (B); (ii) → (C); (iii) → (A); (iv) → (D) (2) (i) →(C); (ii) →(B); (iii) →(D); (iv) →(A) (3) (i) → (D); (ii) → (A); (iii) → (B); (iv) → (C) (4) (i) → (C); (ii) → (D); (iii) → (B); (iv) → (A)

Q37.For the following reaction, equilibrium constant are given: Ss + O2g ⇌SO2g; K1 = 1052 2Ss + 3O2g ⇌2SO3g; K2 = 10129 The equilibrium constant for the reaction, 2SO2g + O2g ⇌2SO3g is: (1) 10154 (2) 1025 (3) 10181 (4) 1077

Q37.The temporary hardness of a water sample is due to compound X. Boiling this sample converts X to compound Y. X and Y, respectively, are: (1) Mg(HCO3)2 and MgCO3 (2) Ca(HCO3)2 and Ca(OH)2 (3) Mg(HCO3)2 and Mg(OH)2 (4) Ca(HCO3)2 and CaO

Q38.Which of the following compounds is not aromatic? (1) (2) (3) (4) JEE Main 2019 (09 Jan Shift 2) JEE Main Previous Year Paper

Q38.The isotopes of hydrogen are: (1) Protium, deuterium and tritium (2) Tritium and protium only (3) Protium and deuterium only (4) Deuterium and tritium only

Q38.The correct statements among (a) to (d) regarding H2 as a fuel are : (i) It produces less pollutants than petrol. (ii) A cylinder of compressed dihydrogen weighs ∼30 times more than a petrol tank producing the same amount of energy. (iii) Dihydrogen is stored in tanks of metal alloys like NaNi5 (iv) On combustion, values of energy released per gram of liquid dihydrogen and LPG are 50 and 142 kJ, respectively. (1) (ii)and(iv)only (2) (i)and(iii)only (3) (ii), (iii)and(iv)only (4) (i), (ii)and(iii)only

Q38.The combination of plots which does not represent isothermal expansion of an ideal gas is (A) (B) JEE Main 2019 (12 Jan Shift 2) JEE Main Previous Year Paper (C) (D) (1) (A) and (D) (2) (B) and (C) (3) (B) and (D) (4) (A) and (C)

Q38.The correct statements among a to d are: a Saline hydrides produce H2 gas when reacted with H2O . b Reaction of LiAlH4 with BF3 leads to B2H6 . c PH3 and CH4 are electron - rich and electron - precise hydrides, respectively. d HF and CH4 are called as molecular hydrides. (1) a, b and c only. (2) a, c and d only. (3) c and d only. (4) a, b, c and d JEE Main 2019 (10 Apr Shift 2) JEE Main Previous Year Paper

Q38.An example of a disproportionation reaction is (1) 2KMnO4 →K2MnO4 + MnO2 + O2 (2) 2MnO4- + 10I- + 16 H+ →2 Mn2 + + 5I2 + 8H2O (3) 2 CuBr →CuBr2 + Cu (4) 2 NaBr + Cl2 →2NaCl + Br2

Q38.The strength of 11.2 volume solution of H2O2 is [Given that, the molar mass of H = 1 g mol-1 and O = 16 g mol-1] (1) 1.7 % (2) 13.6 % (3) 34 % (4) 3.4 %