Practice Questions

Q54.Ka for butyric acid C3H7COOH is 2 × 10-5. ThepH of 0 . 2M solution of butyric acid is____ × 10-1. (Nearest integer) [Given log2 = 0 . 30]

Q55.The elevation in boiling point for 1 molal solution of non-volatile solute A is 3 K. The depression in freezing point for 2 molal solution of A in the same solvent is 6 K. The ratio of Kb and Kf i.e., Kb / Kf is 1: X. The value of X is

Q55.A company dissolves ' x ' amount of CO2 at 298 K in 1 litre of water to prepare soda water. X = ×10−3 g . (nearest integer) (Given: partial pressure of CO2 at 298 K = 0. 835 bar. Henry's law constant for CO2 at 298 K = 1. 67 kbar. Atomic mass of H, C and O is 1, 12 , and 6 g mol−1 , respectively)

Q55.Elevation in boiling point for 1. 5 molal solution of glucose in water is 4 K. The depression in freezing point for 4. 5 molal solution of glucose in water is 4 K. The ratio of molal elevation constant to molal depression constant (Kb/Kf) is

Q55.Ionic radii of cation A+ and anion B− are 102 and 181 pm respectively. These ions are allowed to crystallize into an ionic solid. This crystal has cubic close packing for B−. A+ is present in all octahedral voids. The edge length of the unit cell of the crystal AB is___ pm .

Q55.Two elements A and B which form 0. 15 moles of A2B and AB3 type compounds. If both A2B and AB3 weigh equally, then the atomic weight of A is____times of atomic weight of B. Q56. 2 g of a non-volatile non-electrolyte solute is disolved in 200 g of two different solvents A and B whose ebullioscopic constants are in the ratio of 1 : 8. The elevation in boiling points of A and B are in the ratio x (x : y). The value of y is____(Nearest Integer) y

Q55.A 0. 5 percent solution of potassium chloride was found to freeze at −0. 24 °C. The percentage dissociation of potassium chloride is (Nearest integer) (Molal depression constant for water is 1. 80 K kg mol−1 and molar mass of KCl is 74. 6 g mol−1 )

Q55.Atoms of element X form hcp lattice and those of element Y occupy 32 of its tetrahedral voids. The percentage of element X in the lattice is (Nearest integer)

Q55.A solution of Fe2SO43 is electrolyzed for 'x' min with a current of 1 . 5 A to deposit 0 . 3482 g of Fe. The value of x is - [nearest integer] Given : 1 F = 96500 Cmol-1. Atomic mass of Fe = 56 gmol-1

Q55. BeO reacts with HF in presence of ammonia to give [A] which on thermal decomposition produces [B] and ammonium fluoride. Oxidation state of Be in [A] is Q56. 0. 25 g of an organic compound containing chlorine gave 0. 40 g of silver chloride in Carius estimation. The percentage of chlorine present in the compound is [in nearest integer] (Given: Molar mass of Ag is 108 g mol−1 and that of Cl is 35. 5 g mol−1 )

Q55.For a cell, CusCu2 + 0 . 001M ) Ag+0 . 01MAgsthe cell potential is found to be 0 . 43 V at 298 K. The magnitude of standard electrode potential for Cu2 + | Cu is____ × 10-2 V 𝛩 2 . 303RT Given: EAg+ / Ag = 0 . 80 V and F = 0 . 06 V

Q55.The number of sp3 hybridised carbons in an acyclic neutral compound with molecular formula C4H5N is

Q55.On reaction with stronger oxidizing agent like KIO4 , hydrogen peroxide oxidizes with the evolution of O2 . The oxidation number of I in KIO4 changes to

Q55.For the given reactions Sn2+ + 2e−→Sn ° ° Sn4+ + 4e−→Sn the electrode potentials are ; E Sn2+ / Sn = −0. 140 V and E Sn4+ / Sn = 0. 010 V. The ° magnitude of standard electrode potential for Sn4+ / Sn2+ i.e. E Sn4+ / Sn2+ is____ ×10−2 V(Nearest integer)

Q55.The standard entropy change for the reaction 4Fes + 3O2g →2Fe2O3s is -550 J K-1 at 298 K [Given : The standard enthalpy change for the reaction is -165 kJ mol-1]. The temperature in K at which the reaction attains equilibrium is (Nearest Integer)

Q55.The normality of H2 SO4 in the solution obtained on mixing 100 mL of 0. 1M H2 SO4 with 50 mL of 0. 1M NaOH is____ ×10−1 N .

Q55.While performing a thermodynamics experiment, a student made the following observations, HCl + NaOH →NaCl + H2OΔH = −57. 3 kJ mol−1 CH3 COOH + NaOH →CH3 COONa + H2O ΔH = −55. 3 kJ mol−1 . JEE Main 2022 (25 Jul Shift 2) JEE Main Previous Year Paper The enthalpy of ionization of CH3 COOH as calculated by the student is kJ mol−1 .

Q55.An element M crystallises in a body centred cubic unit cell with a cell edge of 300pm. The density of the element is 6 . 0 g cm-3. The number of atoms present in 180 g of the element is____ × 1023. (Nearest integer) Q56.150 g of acetic acid was contaminated with 10 . 2 g ascorbic acid C6H8O6 to lower down its freezing point by x × 10-1°C. The value of x is____ (Nearest integer). [Given Kf = 3 . 9 K kg mol-1; Molar mass of ascorbic acid = 176 g mol-1]

Q56.When a certain amount of solid A is dissolved in 100 g of water at 25 °C to make a dilute solution, the vapour pressure of the solution is reduced to one-half of that of pure water. The vapour pressure of pure water is 23. 76 mmHg . The number of moles of solute A added is Q57. [A] → [B] Reactant Product If formation of compound [B] follows the first order of kinetics and after 70 minutes the concentration of [A] was found to be half of its initial concentration. Then the rate constant of the reaction is x × 10−6 s−1 . The value of x is____

Q56.In the following reaction ​ The % yield for reaction I is 60% and that of reaction II is 50%. The overall yield of the complete reaction is % Q57. 2NO + 2H2 →N2 + 2H2O The above reaction has been studied at 800 °C . The related data are given in the table below Initial Reaction serial Initial pressure of Initial rate Pressure −dp /s) number H2/ kPa ( dt )/(kPa of NO / kPa 1 65. 6 40. 0 0. 135 2 65. 6 20. 1 0. 033 3 38. 6 65. 6 0. 214 4 19. 2 65. 6 0. 106 The order of the reaction with respect to NO is____

Q56.The osmotic pressure of blood is 7. 47 bar at 300 K . To inject glucose to a patient intravenously, it has to be isotonic with blood. The concentration of glucose solution in gL−1 is (Molar mass of glucose = 180 g mol−1 , R = 0. 083 Lbar−1 mol−1 ) (Nearest integer)

Q56.The separation of two coloured substances was done by paper chromatography. The distances travelled by solvent front, substance A and substance B from the base line are 3. 25 cm. 2. 08 cm and 1. 05 cm . respectively. The ratio of Rf values of A to B is (Answer the nearest integer)

Q56.The cell potential for ZnZn2 + (aq)‖Snx + Sn is 0 . 801V at 298 K. The reaction quotient for the above reaction is 10-2. The number of electrons involved in the given electrochemical cell reaction is _____ . 0 0 2 . 303RT = + 0 . 008 V and = 0 . 06 V) = - 0 . 763 V, ESnx + | Sn (Given EZn2 + ∣Zn F

Q56.A dilute solution of sulphuric acid is electrolysed using a current of 0. 10 A for 2 hours to produce hydrogen and oxygen gas. The total volume of gases produced at STP is cm3 . (Nearest integer) [Given : Faraday constant F = 96500 Cmol−1 at STP, molar volume of an ideal gas is 22. 7 L mol−1 ]

Q56.A flask is filled with equal moles of A and B. The half lives of A and B are 100 s and 50 s respectively and are independent of the initial concentration. The time required for the concentration of A to be four times that of B is____ s. (Given : ln 2 = 0. 693 ) Q57. 2. 0 g of H2 gas is adsorbed on 2. 5 g of platinum powder at 300 K and 1 bar pressure. The volume of the gas adsorbed per gram of the adsorbent is mL (Given : R = 0. 083 L bar K−1 mol−1 )