Practice Questions

Q46. NaClO3 is used, even in spacecrafts, to produce O2. The daily consumption of pure O2 by a person in 492 L at 1 atm, 300K. How much amount of NaClO3, in grams, is required to produce O2 for the daily consumption of a person at 1 atm, 300K ? _____ NaClO3(s) + Fe(s) →O2(g) + NaCl(s) + FeO(s) R = 0 .082 L atm mol−1 K−1

Q46.A spherical balloon of radius 3 cm containing helium gas has a pressure of 48 × 10−3 bar. At the same temperature, the pressure, of a spherical balloon of radius 12 cm containing the same amount of gas will be … … … … . ×10−6 bar.

Q46.The Gibbs energy change (in J) for the given reaction at [Cu2+] = [Sn2+] = 1 M and 298 K is : Cu(s) + Sn2+(aq. ) →Cu2+(aq. ) + Sn(s); = −0 .16 V, E0 = 0 .34 V,Take F = 96500 C mol−1) Cu2+ Cu (E0Sn2+|Sn

Q46.The mole fraction of glucose (C6H12O6) in an aqueous binary solution is 0. 1. The mass percentage of water in it, to the nearest integer, is … … … JEE Main 2020 (03 Sep Shift 1) JEE Main Previous Year Paper

Q46.For the reaction; A(l) →2B(g) ΔU = 2.1kcal, ΔS = 20calK−1 at 300K. Hence ΔG in kcal is _____________.

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.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.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.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.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.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)

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.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.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 _______

Q48.The number of chiral carbons present in the molecule given below is.............. JEE Main 2020 (02 Sep Shift 1) JEE Main Previous Year Paper

Q48.The volume, in mL, of 0. 02 MK2 Cr2 O7, solution required to react with 0. 288g of ferrous oxalate in acidic medium is … … … … (Molar mass of Fe = 56 gmol−1 )

Q48.The heat of combustion of ethanol into carbon dioxides and water is −327 Kcal at constant pressure. The heat evolved (in cal) at constant volume at 27° C (if all gases behave ideally) is (R = 2 calmol−1 K−1) ________

Q48.How much amount of NaCl should be added to 600 g of water (ρ = 1.00g/mL) to decrease the freezing point of water to −0.2 oC? ________. (The freezing point depression constant for water = 2 K kgmol−1 ) Q49. 108 g of silver (molar mass 108 gmol−1 ) is deposited at cathode from AgNO3(aq) solution by a certain quantity of electricity. The volume (in L ) of oxygen gas produced at 273 K and 1 bar pressure from water by the same quantity of electricity is ________

Q48.The osmotic pressure of a solution of NaCl is 0. 10 atm and that of a glucose solution is 0. 20 atm. The osmotic pressure of a solution formed by mixing 1 L of the sodium chloride solution with 2 L of the glucose solution is x × 10−3 atm. x is ________ (nearest integer)

Q48.A sample of milk splits after 60min . at 300K and after 40min . at 400K when the population of Iactobacillus acidophilus in it doubles. The activation energy (in kJ / mol ) for this process is closest to ______________. (Given, R = 8.3Jmol−1K−1, ln( 23 ) = 0.4, e−3 = 4.0 )

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.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)

Q48.An acidic solution of dichromate is electrolyzed for 8 minutes using 2 A current. As per the following equation Cr2 O27 + 14H+ + 6e−→2 Cr3+ + 7H2O The amount of Cr3+ . obtained was 0. 104g. The efficiency of the process (in %) is (Take : F = 960000C, At. mass of chromium = 52)

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______?