Practice Questions

Q46.For a dimerization reaction, JEE Main 2020 (05 Sep Shift 2) JEE Main Previous Year Paper 2A(g) →A2(g) at 298K, ΔU−= −20 kJmol−1, ΔS−= −30 JK−1 mol−1,then the ΔG− will be …..J.

Q46.A soft drink was bottled with a partial pressure of CO2 of 3 bar over the liquid at room temperature. The partial pressure of CO2 over the solution approaches a value of 30 bar when 44 g of CO2 is dissolved in 1 kg of water at room temperature. The approximate pH of the soft drink is ___________ ×10−1 . (First dissociation constant of H2 CO3 = 4. 0 × 10−7; log 2 = 0. 3; density of the soft drink = 1 g mL−1 ) JEE Main 2020 (05 Sep Shift 1) JEE Main Previous Year Paper

Q46.The molarity of HNO3 in a sample which has density 1.4 g/mL and mass percentage of 63% is ________ (Molecular Weight of HNO3 = 63 ) JEE Main 2020 (09 Jan Shift 1) JEE Main Previous Year Paper

Q46.The ratio of the mass percentages of ' C & H ' and ' C & O' of a saturated acyclic organic compound ' X ' are 4 : 1 and 3 : 4 respectively. Then, the moles of oxygen gas required for complete combustion of two moles of organic compound ' X' is_______

Q47.The work function of sodium metal is 4. 41 × 10−19J. If photons of wavelength 300 nm are incident on the metal, the kinetics energy of the ejected electrons will be (h = 6. 63 × 10−34J s; c = 3 × 108 m s−1) __________ ×10−21J

Q47.The magnitude of work done by a gas that undergoes a reversible expansion along the path ABC shown in the figure is _________. JEE Main 2020 (08 Jan Shift 1) JEE Main Previous Year Paper

Q47.If the solubility product of AB2 is 3. 20 × 10−11 M3 , then the solubility of AB2 in pure water is _______ ×10−4 mol L−1 [Assuming that neither kind of ion reacts with water]

Q47.If 250 cm3 of an aqueous solution containing 0. 73g of a protein A is isotonic with one litre of another aqueous solution containing 1. 65g of a protein B, at 298K, the ratio of the molecular masses of A and B is ___________ ×10−2 (to the nearest integer). JEE Main 2020 (03 Sep Shift 2) JEE Main Previous Year Paper

Q47.At constant volume, 4 mol of an ideal gas when heated from 300K to 500K changes its internal energy by 5000J. The molar heat capacity at constant volume is ________ JEE Main 2020 (08 Jan Shift 2) JEE Main Previous Year Paper

Q47.The volume strength of 8. 9 MH2 O2 solution calculated at 273 K and 1 atm is ........ (R = 0 .0821 L atm K−1 mol−1) (rounded off to the nearest integer)

Q47.The hardness of a water sample containing 10−3 M MgSO4 expressed as CaCO3 equivalents (in ppm ) is . (molar mass of MgSO4 is 120.37 g/mol )

Q47.Consider the following equations : 2 Fe2+ + H2O2 →xA + yB (in basic medium) 2 MnO−4 + 6H+ + 5H2O2 →x′C + y′D + z′E JEE Main 2020 (04 Sep Shift 2) JEE Main Previous Year Paper (in acidic medium) The sum of the stoichiometric coefficients x, y, x′, y′ and z′ for products A, B, C, D and E respectively, is _______

Q47.A cylinder containing an ideal gas ( 0.1mol of 1.0dm3 ) is in thermal equilibrium with a large volume of 0.5 molal aqueous solution of ethylene glycol at its freezing point. If the stoppers S1 and S2 (as shown in the figure) are suddenly withdrawn, the volume of the gas in litres after equilibrium is achieved will be _____________. (Given, Kf(water) = 2.0Kkgmol−1, R = 0.08dm3atmK−1mol−1)

Q47.The internal energy change (in J) when 90 g of water undergoes complete evaporation at 100°C is .............. (Given : ΔHvap for water at 373 K = 41 kJ / mol, R = 8. 314 JK−1 mol−1 )

Q47.Two solutions, A and B, each of 100L was made by dissolving 4g of NaOH and 9.8g of H2SO4 in water, respectively. The pH of the resultant solution obtained from mixing 40L of solution A and 10L of solution B is ____________. (log 2 = 0. 3)

Q47.The minimum number of moles of O2 required for complete combustion of 1 mole of propane and 2 moles of butane is..............

Q47.For a reaction X + Y = 2Z, 1. 0 mol of X, 1. 5 mol of Y and 0. 5 mol of Z were taken in a 1L vessel and allowed to react. At equilibrium, the concentration of Z was 1. 0 molL−1. the equilibrium constant of the reaction is … … … … 15x . The value of x is … … .

Q47.In an estimation of bromine by Carius method, 1. 6g of an organic compound gave 1. 88g of AgBr. The mass percentage of bromine in the compound is … . . (Atomic mass, Ag = 108, Br = 80 gmol−1

Q47.A 20. 0 mL solution containing 0. 2 g impure H2O2 reacts completely with 0. 316 g of KMnO4 in acid solution. The purity of H2O2 (in % ) is______ (mol. wt. of H2O2 = 34; mol. wt. of KMnO4 = 158)

Q48.During the nuclear explosion, one of the products is 90Sr with half life of 6.93 years. If 1μg of 90Sr was absorbed in the bones of a newly born baby in place of Ca, how much time, in years, is required to reduce it JEE Main 2020 (07 Jan Shift 1) JEE Main Previous Year Paper by 90% if it is not lost metabolically ____________.

Q48.At 300 K, the vapour pressure of a solution containing 1 mole of n -hexane and 3 moles of n -heptane is 550 mm of Hg. At the same temperature, if one more mole of n -heptane is added to this solution, the vapour pressure of the solution increases by 10 mm of Hg . What is the vapour pressure in mmHg of n - heptane in its pure state______?

Q48.The rate of a reaction decreased by 3. 555 times when the temperature was changed from 40 °C to 30 °C . the activation energy (in kJ mol−1 ) of the reaction is ________ .

Q48.Consider the following reactions: NaCl + K2Cr2O7 + H2SO4 →(A)+ side products (Conc.) (A) + NaOH →(B)+ side products (B) + H2SO4 + H2O2 →(C)+ side products (dilute) The sum of the total number of atoms in one molecule each of (A), (B) and (C) is ________

Q48.Ferrous sulphate heptahydrate is used to fortify foods with iron. The amount (in grams) of the salt required to achieve 10ppm of iron in 100kg of wheat is ____________. Atomic weight: Fe = 55.85; S = 32.00; O = 16.00

Q48.In the following sequence of reactions the maximum number of atoms present in molecule ‘ C ’ in one plane is_______ Red hot CH3Cl(1.eq) −−A → B → C Cu tube Anhydrous AlCl3 (A is a lowest molecular weight alkyne)