Practice Questions

Q55.For the reaction A + B ⇌2C the value of equilibrium constant is 100 at 298 K. If the initial concentration of all the three species is 1 M each, then the equilibrium concentration of C is x × 10-1 M. The value of x is _______. (Nearest integer)

Q55.For the reaction 2NO2 ( 𝑔) ⇌N2O4 ( g ) , when ΔS = - 176 . 0 J K-1 and ΔH = - 57 . 8 kJ mol-1 the magnitude of ΔG at 298 K for the reaction is _____ kJmol-1. (Nearest integer)

Q55.Two salts A2X and MX have the same value of solubility product of 4. 0 × 10−12 . The ratio of their molar solubilizes i.e. S(A2X) S(MX) = ________. (Round off to the Nearest Integer). Q56. 2 MnO−4 + bC2 O2−4 + cH+ →xMn2+ + yCO2 + zH2 O If the above equation is balanced with integer coefficients, the value of c is _______ . (Round off to the Nearest Integer). o

Q55.In Duma's method of estimation of nitrogen, 0. 1840 g of an organic compound gave 30 mL of nitrogen collected at 287 K and 758 mm of Hg pressure. The percentage composition of nitrogen in the compound is ______. (Round off to the Nearest Integer). [Given : Aqueous tension at 287 K = 14 mm of Hg ]

Q55.The standard enthalpies of formation of Al2 O3 and CaO are −1675 kJ mol−1 and −635 kJ mol−1 respectively. For the reaction 3CaO + 2Al →3Ca + Al2 O3 the standard reaction enthalpy ΔrH0 = ________ kJ. (Round off to the Nearest Integer). JEE Main 2021 (17 Mar Shift 1) JEE Main Previous Year Paper Q56. 0. 01 moles of a weak acid HA (Ka = 2. 0 × 10−6) is dissolved in 1. 0 L of 0. 1M HCl solution. The degree of dissociation of HA is __________ ×10−5 (Round off to the Nearest Integer). [Neglect volume change on adding HA and assume degree of dissociation << 1 ] Q57. 15 mL of aqueous solution of Fe2+ in acidic medium completely reacted with 20 mL of 0. 03 M aqueous Cr2 O72−. The molarity of the Fe2+ solution is _______ ×10−2M (Round off to the Nearest Integer).

Q55. KBr is doped with 10−5 mole percent of SrBr2 The number of cationic vacancies in 1 g of KBr crystal is 1014 . (Round off to the Nearest Integer). [Atomic Mass : K = 39. 1u, Br = 79. 9u, NA = 6. 023 × 1023]

Q55.In order to prepare a buffer solution of pH 5. 74, sodium acetate is added to acetic acid. If the concentration of acetic acid in the buffer is 1. 0 M, the concentration of sodium acetate in the buffer is ______ M. (Round off to the Nearest Integer). [Given : pKa(acetic acid) = 4. 74] Q56. 2 molal solution of a weak acid HA has a freezing point of 3. 885°C. The degree of dissociation of this acid is ______ ×10−3. (Round off to the Nearest Integer). [ Given : Molal depression constant of water = 1. 85 K kg mol−1 Freezing point of pure water = 0°C]

Q56.The molar solubility of Zn ( OH ) in 0 . 1MNaOH solution is 𝑥× 10-18M . The value of 𝑥 is _____ . (Nearest 2 integer) Given : The solubility product of Zn(OH ) is 2 × 10-20 2

Q56.The vapour pressures of A and B at 25°C are 90 mmHg and 15 mm Hg respectively. If A and B are mixed such that the mole fraction of A in the mixture is 0. 6, then the mole fraction of B in the vapour phase is x × 10−1. The value of x is (Nearest integer)

Q56.Sodium oxide reacts with water to produce sodium hydroxide. 20 . 0 g of sodium oxide is dissolved in 500 mL of water. Neglecting the change in volume, the concentration of the resulting NaOH solution is _________ × 10-1M . (Nearest integer) [Atomic mass : Na = 23 . 0, O = 16 . 0, H = 1 . 0] Q57.1 . 22 g of an organic acid is separately dissolved in 100 g of benzene Kb = 2 . 6 K kg mol-1 and 100 g of acetone Kb = 1 . 7 K kg mol-1 . The acid is known to dimerize in benzene but remain as a monomer in acetone. The boiling point of the solution in acetone increases by 0 . 17°C . The increase in boiling point of solution in benzene in∘C is x × 10-2 . The value of x is (Nearest integer) [Atomic mass : C = 12 . 0, H = 1 . 0, O = 16 . 0]

Q56.Consider the following cell reaction Cd(s) + Hg2 SO4( s) + 95 H2O(l) ⇌CdSO4 ⋅95 H2O(s) + 2 Hg(l). The value of E0cell is 4. 315 V at 25°C. If ΔH°= −825. 2 kJ mol−1, the standard entropy change ΔS° in J K−1 is _________ . (Nearest integer) [Given : Faraday constant = 96487 C mol−1 ]

Q56.Using the provided information in the following paper chromatogram: JEE Main 2021 (25 Feb Shift 1) JEE Main Previous Year Paper The calculated Rf value of A is _____ × 10−1 .

Q56.The dihedral angle in staggered form of Newmann's projection of 1, 1, 1 -Trichloro ethane is … … … degree. (Round off to the nearest integer) (Round off to the nearest integer)

Q56. C6H6 freezes at 5. 5°C. The temperature at which a solution of 10 g of C4H10 in 200 g of C6H6 freeze is _______ ∘C. (nearest integer value), (The molal freezing point depression constant of C6H6 is 5. 12°C/m.)

Q56.At 20°C, the vapour pressure of benzene is 70 torr and that of methyl benzene is 20 torr. The mole fraction of benzene in the vapour phase at 20°C above an equimolar mixture of benzene and methyl benzene is __ × 10−2. (Nearest integer)

Q56.Of the following four aqueous solutions, the total number of those solutions whose freezing point is lower than that of 0. 10 MC2 H5 OH is (Integer answer) (i) 0. 10M Ba3 (PO4)2 (ii) 0. 10M Na2 SO4 (iii) 0. 10M KCl (iv) 0. 10M Li3 PO4

Q56.A 1 molal K4 Fe(CN)6 solution has a degree of dissociation of 0. 4 . Its boiling point is equal to that of another solution which contains 18. 1 weight percent of a non electrolytic solute A . The molar mass of A is _____ u. (Round off to the Nearest Integer). [Density of water = 1. 0 g cm−3]

Q56.If a compound AB dissociates to the extent of 75% in an aqueous solution, the molality of the solution which shows a 2. 5 K rise in the boiling point of the solution is ___ molal. (Rounded-off to the nearest integer) [Kb = 0. 52K kg mol−1].

Q56.The number of moles of CuO, that will be utilized in Dumas method for estimating nitrogen in a sample of 57. 5 g of N, N− dimethylaminopentane is ________ ×10−2. (Nearest integer) Q57. 200 mL of 0. 2 M HCl is mixed with 300 mL of 0. 1 M NaOH. The molar heat of neutralization of this reaction is −57. 1 kJ. The increase in temperature in ∘C of the system on mixing is x × 10−2. The value of x is (Nearest integer) [Given: Specific heat of water = 4. 18 J g−1 K−1 JEE Main 2021 (27 Aug Shift 1) JEE Main Previous Year Paper Density of water = 1. 00 g cm−3 ] (Assume no volume change on mixing)

Q56.When 5. 1 g of solid NH4 HS is introduced into a two litre evacuated flask at 27°C, 20% of the solid decomposes into gaseous ammonia and hydrogen sulphide. The Kp for the reaction at 27°C is x × 10−2 . The JEE Main 2021 (27 Aug Shift 2) JEE Main Previous Year Paper value of x is (Integer answer) [Given 1R = 0. 082 L atm K−1 mol−1] Q57. 40 g of glucose (Molar mass = 180) is mixed with 200 mL of water. The freezing point of solution is __K. (Nearest integer) [Given : Kf = 1. 86 K kg mol−1; Density of water = 1. 00 g cm−3; Freezing point of water = 273. 15 K]

Q56.A copper complex crystallising in a CCP lattice with a cell edge of 0. 4518 nm has been revealed by employing X -ray diffraction studies. The density of a copper complex is found to be 7. 62 g cm−3. The molar mass of copper complex is gmol−1 (Nearest integer): [ Given : NA = 6. 022 × 1023 mol−1]

Q56.When 10 mL of an aqueous solution of Fe2 + ions was titrated in the presence of dil H2SO4 using diphenylamine indicator, 15 mL of 0 . 02 M solution of K2Cr2O7 was required to get the end point. The molarity of the solution containing Fe2 + ions is x × 10-2 M. The value of x is ______. (Nearest integer)

Q56.A chloro compound "A". (i) forms aldehydes on ozonolysis followed by the hydrolysis. (ii) when vaporized completely 1. 53 g of A, gives 448 mL of vapour at STP. The number of carbon atoms in a molecule of compound A is Q57. 83 g of ethylene glycol dissolved in 625 g of water. The freezing point of the solution is ..... K. (Nearest integer) [Use : Molal Freezing point depression constant of water = 1. 86 K kg mol−1 Freezing point of water = 273 K Atomic masses : C : 12. 0u, O : 16. 0u, H : 1. 0u]

Q56.The reaction of sulphur in alkaline medium is given below: S8s + a OHaq−→b Saq2 −+ c S2O3aq2 −+ d H2Ol The values of '𝑎' is______ (Integer answer)

Q56.The number of octahedral voids per lattice site in a lattice is_. (Rounded off to the nearest integer)