Practice Questions

Q56. Ga (atomic mass 70 u ) crystallizes in a hexagonal close packed structure. The total number of voids in 0. 581 g of Ga is ________ ×1021 . (Round off to the Nearest Integer).

Q56.A solute A dimerizes in water. The boiling point of a 2 molal solution of A is 100. 52∘C. The percentage association of A is ___ . (Round off to the Nearest integer) Use : Kb for water = 0. 52 K kg mol−1 Boiling point of water = 100°C

Q56.An organic compound is subjected to chlorination to get compound A using 5. 0 g of chlorine. When 0. 5 g of compound A is reacted with AgNO3 [Carius Method], the percentage of chlorine in compound A is when it forms 0. 3849 g of AgCl. (Round off to the Nearest Integer) (Atomic masses of Ag and Cl are 107. 87 and 35. 5 respectively) Q57. 1. 46 g of a biopolymer dissolved in a 100 mL water at 300 K exerted an osmotic pressure of 2. 42 × 10−3 bar The molar mass of the biopolymer is −× 104 g mol−1. (Round off to the Nearest Integer) [Use: R = 0. 083 L bar mol−1 K−1]

Q57.These are physical properties of an element (A) Sublimation enthalpy (B) Ionisation enthalpy (C) Hydration enthalpy (D) Electron gain enthalpy The total number of above properties that affect the reduction potential is (Integer answer)

Q57.If 80 g of copper sulphate CuSO4 · 5H2O is dissolved in deionised water to make 5 L of solution. The concentration of the copper sulphate solution is 𝑥× 10-3 mol 𝐿-1 . The value of 𝑥 is _____. [ Atomic masses Cu : 63 . 54u, S : 32u, O : 16u, H : 1u]

Q57.If the concentration of glucose (C6H12O6) in blood is 0. 72 gL−1, the molarity of glucose in blood is −× 10−3M (Nearest integer): [Given : Atomic mass of C = 12, H = 1, O = 16 u] + 2 Ag(s)

Q57.A certain element crystallises in a bcc lattice of unit cell edge length 27 A. If the same element under the same o conditions crystallises in the fcc lattice, the edge length of the unit cell in A will be __________. (Round off to the Nearest Integer). [Assume each lattice point has a single atom] [Assume √3 = 1. 73, √2 = 1. 41]

Q57.At 363 K, the vapour pressure of A is 21 kPa and that of B is 18 kPa. One mole of A and 2 moles of B are mixed. Assuming that this solution is ideal, the vapour pressure of the mixture is___________ kPa. (Round of to the Nearest Integer ).

Q57.The inactivation rate of a viral preparation is proportional to the amount of virus. In the first minute after preparation, 10% of the virus is inactivated. The rate constant for viral inactivation is ___ × 10−3 min−1. (Nearest integer) [Use : ln 10 = 2. 303; log10 3 = 0. 477 property of logarithm : log xy = y log x]

Q57.Number of amphoteric compounds among the following is (A) BeO JEE Main 2021 (24 Feb Shift 1) JEE Main Previous Year Paper (B) BaO (C) BeOH2 (D) Sr OH2

Q57.For the reaction 2 Fe3+(aq) + 2I−(aq) →2 Fe2+(aq) + I2( s) the magnitude of the standard molar free energy change, ΔrG∘m = − ______ kJ (Round off to the Nearest Integer). JEE Main 2021 (18 Mar Shift 1) JEE Main Previous Year Paper Q58. 2 NO(g) + Cl2( g) ⇌2 NOCl(s) This reaction was studied at −10°C and the following data was obtained run [NO]0 [Cl2]0 r0 1 0.10 0.10 0.18 2 0.10 0.20 0.35 3 0.20 0.20 1.40 [NO]0 and [Cl2]0 are the initial concentrations and r0 is the initial reaction rate. The overall order of the reaction is (Round off to the Nearest Integer).

Q57.For a first order reaction, the ratio of the time for 75% completion of a reaction to the time for 50% completion is ___________ . (Integer answer)

Q57.In a solvent 50% of an acid HA dimerizes and the rest dissociates. The van't Hoff factor of the acid is _____ ×10−2 (Round off to the nearest integer)

Q57.The magnitude of the change in oxidising power of the MnO−4 / Mn2+ couple is x × 10−4 V if the H+ concentration is decreased from 1 M to 10−4M at 25°C. (Assume concentration of MnO−4 and Mn2+ to be same on change in H+ concentration). The value of x is __________. (Rounded off to the nearest integer) [Given: 2.303 RT = 0. 059] F

Q57.Consider the following reaction MnO−4 + 8H+ + 5e−→Mn+2 + 4H2O , E°= 1. 51 V The quantity of electricity required in Faraday to reduce five moles of MnO−4 is

Q57.A KCl solution of conductivity 0. 14 S m−1 shows a resistance of 4. 19Ω in a conductivity cell. If the same cell is filled with an HCl solution, the resistance drops to 1. 03Ω . The conductivity of the HCl solution is ____ ×10−2 S m−1 . (Round off to the Nearest Integer).

Q57.Consider the following chemical reaction. 1) Red hot Fe tube, 873 K CH ≡CH 2) CO,HCl,AlCl3 > Product The number of sp2 hybridized carbon atom(s) present in the product is Q58. 1 molal aqueous solution of an electrolyte A2 B3 is 60% ionised. The boiling point of the solution at 1 atm is _____ K. (Rounded-off to the nearest integer) [Given Kb for (H2O) = 0. 52 K kg mol−1 ]

Q57.When 12. 2 g of benzoic acid is dissolved in 100 g of water, the freezing point of solution was found to be −0. 93 °C(Kf(H2O) = 1. 86 K kg mol−1). The number (n) of benzoic acid molecules associated (assuming 100% association) is _.

Q57.Copper reduces NO−3 into NO and NO2 depending upon the concentration of HNO3 in solution. (Assuming fixed [Cu2+] and PNO = PNO2 ), the HNO3 concentration at which the thermodynamic tendency for reduction of NO−3 into NO and NO2 by copper is same is 10x M. The value of 2x is ___. (Rounded-off to the nearest integer) [Given, Eo = 0. 34 V, Eo = 0. 96 V, Eo = 0. 79 V and at 298 K, RTF (2. 303) = 0. 059] Cu2+ / Cu NO−3 / NO NO−3 / NO2

Q57. Consider the above chemical reaction. The total number of stereoisomers possible for Product "P" is _________

Q57.The molar conductivity at infinite dilution of barium chloride, sulphuric arid and hydrochloric acid are 280, 860 426 Scm2 mol−1 respectively. The molar conductivity at infinite dilution of barium sulphate is ___ Scm2 mol−1 ( Round off to the Nearest Integer).

Q57. The number of sigma bonds in is _______.

Q57.Potassium chlorate is prepared by electrolysis of KCl in basic solution as shown by following equation. 6 OH−+ Cl−→ClO−3 + 3H2O + 6e− A current of xA has to be passed for 10 h to produce 10. 0 g of potassium chlorate. the value of x is __________. (Nearest integer) (Molar mass of KClO3 = 122. 6 g mol−1 F = 96500 C )

Q58. Emf of the following cell at 298 K in V is x × 10−2 Zn Zn2+(0. 1M) Ag+(0. 01M) Ag The value of x is ________________ (Rounded off to the nearest integer) : Eθ = −0. 76 V; Eθ Ag+ / Ag [Given = +0. 80 V; 2.303F RT = 0. 059] Zn2+ / Zn

Q58.A reaction has a half life of 1 min . The time required for 99. 9% completion of the reaction is ___ min. (Round off to the Nearest integer) [Use : ln 2 = 0. 69, ln 10 = 2. 3 ]