Practice Questions

Q54.Value of KP for the equilibrium reaction N2O4( g) ⇌2 NO2( g) at 288 K is 47. 9. The KC for this reaction at same temperature is (Nearest integer) (R = 0. 083 L bar K−1 mol−1)

Q54.An empty LPG cylinder weighs 14 . 8 kg. When full, it weighs 29 . 0 kg and shows a pressure of 3 . 47 atm . In the course of use at ambient temperature, the mass of the cylinder is reduced to 23 . 0 kg . The final pressure inside the cylinder is _____ atm. (Nearest integer) (Assume LPG to be an ideal gas) JEE Main 2021 (01 Sep Shift 2) JEE Main Previous Year Paper

Q55.The reaction rate for the reaction [PtCl4]2−+ H2O ⇌[Pt(H2O) Cl3]−+ Cl− was measured as a function of concentrations of different species. It was observed that −d[[PtCl4]2−] −2. 4 × 10−3[[Pt(H2O) Cl3]−][Cl−] dt = 4. 8 × 10−5[[PtCl4]2−] where square brackets are used to denote molar concentrations. The equilibrium constant Kc = X (Nearest integer) JEE Main 2021 (26 Aug Shift 2) JEE Main Previous Year Paper Value of 1 is (question is modified.) X

Q55.When 10 mL of an aqueous solution of KMnO4 was titrated in acidic medium, equal volume of 0. 1M of an aqueous solution of ferrous sulphate was required for complete discharge of colour. The strength of KMnO4 in grams per litre is _______ ×10−2. (Nearest integer) [Atomic mass of K = 39, Mn = 55, O = 16 ]

Q55.Data given for the following reaction is as follows : FeO(s) + C(graphite) ⟶Fe(s) + CO(g) Substance ΔfH°(kJmol−1) ΔS°(Jmol−1 K−1) FeO(s) −266. 3 57. 49 C(graphite) 0 5. 74 Fe(s) 0 27. 28 CO(g) −110. 5 197. 6 The minimum temperature in K at which the reaction becomes spontaneous is_____.(Integer answer)

Q55.The number of acyclic structural isomers (including geometrical isomers) for pentene are

Q55.In mildly alkaline medium, thiosulphate ion is oxidized by MnO−4 to ′′A′′. The oxidation state of sulphur in ′′A′′ is_

Q55.At 1990 K and 1 atm pressure, there are equal number of Cl2 molecules and Cl atoms in the reaction mixture. The value of Kp for the reaction Cl2g = 2Clg under the above conditions is 𝑥× 10-1 . The value of x is______(Rounded off to the 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. 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.The solubility product of PbI2 is 8. 0 × 10−9. The solubility of lead iodide in 0. 1 molar solution of lead nitrate is x × 10−6 mol /L. The value of x is _________ (Rounded off to the nearest integer) [Given √2 = 1. 41]

Q55.The unit cell of copper corresponds to a face centered cube of edge length 3. 596 Å with one copper atom at each lattice point. The calculated density of copper in kg /m3 is ___ . [Molar mass of Cu : 63. 54 g; Avogadro Number = 6. 022 × 1023 J]

Q55. PCl5 ⇌PCl3 + Cl2 Kc = 1. 844 3. 0 moles of PCl5 is introduced in a 1L closed reaction vessel at 380 K. The number of moles of PCl5 at equilibrium is — × 10−3 (Round off to the Nearest Integer)

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]

Q55.Diamond has a three dimensional structure of C atoms formed by covalent bonds. The structure of diamond has face centred cubic lattice where 50% of the tetrahedral voids are also occupied by carbon atoms. The number of carbon atoms present per unit cell of diamond is ________.

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.Assuming that Ba(OH)2 is completely ionised in aqueous solution under the given conditions the concentration of H3O+ ions in 0. 005M aqueous solution of Ba(OH)2 at 298 K is _________ ×10−12 mol L−1. (Nearest integer) Q56. 0. 8 g of an organic compound was analysed by Kjeldahl's method for the estimation of nitrogen. If the percentage of nitrogen in the compound was found to be 42%, then....... mL of 1M H2 SO4 would have been neutralized by the ammonia evolved during the analysis. JEE Main 2021 (25 Jul Shift 2) JEE Main Previous Year Paper

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 ]

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

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. 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.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.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.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]