Practice Questions

Q53.The sum of number of lone pairs of electrons present on the central atoms of XeO3, XeOF4 and XeF6 is

Q53.Manganese (VI) has ability to disproportionate in acidic solution. The difference in oxidation states of two ions it forms in acidic solution is Q54. 0. 2 g of an organic compound was subjected to estimation of nitrogen by Dumas method in which volume of N2 evolved (at STP) was found to be 22. 400 mL. The percentage of nitrogen in the compound is - [nearest integer] (Given: Molar mass of N2 is 28 g mol−1 , Molar volume of N2 at STP : 22. 4 L)

Q53.The enthalpy of combustion of propane, graphite and dihydrogen at 298 K are: -2220 . 0 kJ mol-1, -393 . 5 kJ mol-1 and -285 . 8 kJ mol-1 respectively. The magnitude enthalpy of formation of propane C3H8 is _____ kJmol-1. (Nearest integer)

Q53.Amongst SF4, XeF4, CF4 and H2O, the number of species with two lone pairs of electrons is

Q53.The number of paramagnetic species among the following is B2, Li2, C2, C2- , O22 - , O2+ and He2+

Q53.Kjeldahl's method was used for the estimation of nitrogen in an organic compound. The ammonia evolved from 0. 55 g of the compound neutralised 12. 5 mL of 1M H2 SO4 solution. The percentage of nitrogen in the compound is (Nearest integer)

Q54.At 600 K, 2 mol of NO are mixed with 1 mol of O2 . 2 NO(g) + O2(g) ⇄2 NO2(g) The reaction occurring as above comes to equilibrium under a total pressure of 1 atm. Analysis of the system shows that 0. 6 mol of oxygen are present at equilibrium. The equilibrium constant for the reaction is____.

Q54. A fish swimming in water body when taken out from the water body is covered with a film of water of weight 36 g . When it is subjected to cooking at 100 °C, then the internal energy for vaporization in kJmol−1 is integer] [Assume steam to be an ideal gas. Given ΔvapH⊖ for water at 373 K and 1 bar is 41. 1 kJ mol−1 : R = 8. 31 J K−1 mol−1 ] Q55. 40% of HI undergoes decomposition to H2 and I2 at 300 K. ΔGΘ for this decompostion reaction at one atmopsphere pressure is____ Jmol−1 -[nearest integer] (Use R = 8. 31 JK−1 mol−1; log 2 = 0. 3010, ln 10 = 2. 3, log 3 = 0. 477)

Q54.Compound ' P' on nitration with dil. HNO3 yields two isomers (A) and (B). These isomers can be separated by steam distillations. Isomers (A) and (B) show the intramolecular and intermolecular hydrogen bonding respectively. Compound (P) on reaction with conc. HNO3 yields a yellow compound ' C', a strong acid. The number of oxygen atoms is present in compound ' C'

Q54.The number of chiral alcohol(s) with molecular formula C4H10O is ________ (Assume stereoisomers as different chiral alcohols)

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]

Q54.While estimating the nitrogen present in an organic compound by Kjeldahl's method, the ammonia evolved from 0 . 25 g of the compound neutralized 2 . 5 mL of 2MH2SO4. The percentage of nitrogen present in organic compound is _____ .

Q54.At 310 K, the solubility of CaF2 in water is 2. 34 × 10−3 g/100 mL . The solubility product of CaF2 is ---- ×10−8(mol /L)3 (nearest integer). (Given molar mass : CaF2 = 78 g mol−1 ) Q55. 20 mL of 0. 02 MK2 Cr2 O7 solution is used for the titration of 10 mL of Fe2+ solution in the acidic medium. The molarity of Fe2+ solution is____ ×10−2M

Q54.The longest wavelength of light that can be used for the ionisation of lithium ion $\mathrm{(Li^{2+})}$ is x × 10-8 m. The value of x is (Nearest Integer) (Given : Energy of the electron in the first shell of the hydrogen atom is -2 . 2 × 10-18 J; h = 6 . 63 × 10-34Js and c = 3 × 108 ms-1)

Q54.The major product ' A' of the following given reaction has sp2 hybridized carbon atoms. JEE Main 2022 (24 Jun Shift 1) JEE Main Previous Year Paper H+ 2, 7 -Dimethyl- 2, 6 -octadiene → A Major Product

Q54.Metal deficiency defect is shown by Fe0.93 O. In the crystal, some Fe2+ cations are missing and loss of positive charge is compensated by the presence of Fe3+ ions. The percentage of Fe2+ ions in the Fe0.93 O crystals is____(Nearest integer)

Q54.A mixture of hydrogen and oxygen contains 40% hydrogen by mass when the pressure is 2. 2 bar. The partial pressure of hydrogen is bar. Q55. 2. 4 g coal is burnt in a bomb calorimeter in excess of oxygen at 298 K and 1 atm pressure. The temperature of the calorimeter rises from 298 K to 300 K. The enthalpy change during the combustion of coal is −x kJ mol−1 . The value of x is_____(Given : Heat capacity of bomb calorimeter 20. 0 kJK−1 . Assume coal to be pure carbon)

Q54.In bromination of Propyne, with Bromine 1, 1, 2, 2-tetrabromopropane is obtained in 27% yield. The amount of 1, 1, 2, 2 tetrabromopropane obtained from 1 g of Bromine in this reaction is_____ ×10−1 g . (Molar Mass : Bromine = 80 g/ mol)

Q54.A 2. 0 g sample containing MnO2 is treated with HCl liberating Cl2 . The Cl2 gas is passed into a solution of KI and 60. 0 mL of 0. 1 MNaS2 O3 is required to titrate the liberated iodine. The percentage of MnO2 in the sample is____. Nearest integer) [Atomic masses (in u) Mn = 55; Cl = 35. 5 : O = 16, I = 127, Na = 23, K = 39, S = 32 ]

Q54.The neutralization occurs when 10 mL of 0 . 1 M acid 'A' is allowed to react with 30 mL of 0 . 05 M base MOH2. The basicity of the acid 'A' is [M is a metal]

Q54.A gas ( Molar mass = 280 g mol−1 ) was burnt in excess O2 in a constant volume calorimeter and during combustion the temperature of calorimeter increased from 298. 0 K to 298. 45 K . If the heat capacity of calorimeter is 2. 5 kJ K−1 and enthalpy of combustion of gas is 9 kJ mol−1 then amount of gas burnt is____ g .

Q54. pH value of 0. 001 MNaOH solution is

Q54.A sealed flask with a capacity of 2 dm3 contains 11 g of propane gas. The flask is so weak that it will burst if the pressure becomes 2 MPa. The minimum temperature at which the flask will burst is ∘C. [Nearest integer] (Given: R = 8. 3 J K−1 mol−1 . Atomic masses of C and H are 12u and 1u respectively.) (Assume that propane behaves as an ideal gas.)

Q54.Observe structures of the following compounds The total number of structures/compounds which possess asymmetric carbon atoms is Q55. 1. 2 mL of acetic acid is dissolved in water to make 2. 0 L of solution. The depression in freezing point observed for this strength of acid is 0. 0198 °C . The percentage of dissociation of the acid is (Nearest integer) [Given : Density of acetic acid is 1. 02 g mL−1 Molar mass of acetic acid is 60 g mol−1 Kf(H2O) = 1. 85 K kg mol−1 ]

Q55.In the estimation of bromine, 0. 5 g of an organic compound gave 0. 40 g of silver bromide. The percentage of bromine in the given compound is % (nearest integer) (Relative atomic masses of Ag and Br are 108u and 80u , respectively).