Practice Questions

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.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.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.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 If the stoppers S1 and S2 (as shown in the figure) are suddenly withdrawn, the volume of the gas in litres after equilibrium is achieved will be _____________.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 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.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.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.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.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.The minimum number of moles of O2 required for complete combustion of 1 mole of propane and 2 moles of butane is..............

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 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.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.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.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.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.The total number of monohalogenated organic products in the following (including stereoisomers) reaction is (i) H2/ Ni /Δ −A → (Simplest optically active alkene) (ii) X2/Δ

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.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.The elevation of boiling point of 0. 10m aqueous CrCl3. xNH3 solution is two times that of 0. 05 m aqueous CaCl2 solution. The value of x is … … … … . . [Assume 100% ionisation of the complex and CaCl2, coordination number of Cr as 6, and that all NH3 molecules are present inside the coordination sphere]

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.An oxidation-reduction reaction in which 3 electrons are transferred has a ΔG0 of 17. 37 kJ mol−1 at 25°C. The value of Eocell (in V) is _______ ×10−2 . (1F = 96500 C mol−1)

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)