Practice Questions

Q54.The number of moles of NH3, that must be added to 2 L of 0. 80 MAgNO3 in order to reduce the concentration of Ag+ ions to 5. 0 × 10−8M(Kformation for [Ag (NH3)2]+ = 1. 0 × 108) is __________. (Nearest integer) [Assume no volume change on adding NH3 ]

Q54.The number of hydrogen bonded water molecule(s) associated with stoichiometry CuSO4 ⋅5H2O is __________ .

Q54.The pressure exerted by a non-reactive gaseous mixture of 6. 4 g of methane and 8. 8 g of carbon dioxide in a 10 L vessel at 27°C is _____ kPa. (Round off to the Nearest Integer). [Assume gases are ideal, R = 8. 314 J mol−1 K−1 Atomic masses: C : 12. 0 u, H : 1. 0 u, O : 16. 0 u ]

Q55.The ratio of number of water molecules in Mohr's salt and potash alum is ×10−1. (Integer answer)

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.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.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.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.The molarity of the solution prepared by dissolving 6. 3 g of oxalic acid (H2C2O4 ⋅2H2O) in 250 mL of water in mol L−1 is x × 10−2. The value of x is _________ . (Nearest integer) [Atomic mass : H : 1. 0, C : 12. 0, 0 : 16. 0 J]

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.Dichromate ion is treated with base, the oxidation number of Cr in the product formed is Q56. 224 mL of SO2(g) at 298 K and 1 atm is passed through 100 mL of 0. 1 M NaOH solution. The non-volatile solute produced is dissolved in 36 g of water. The lowering of vapour pressure of solution (assuming the solution is dilute) ( P°(H2O)= 24 mm of Hg ) is x × 10−2 mm of Hg the value of x is (Integer answer)

Q55.The empirical formula for a compound with a cubic close packed arrangement of anions and with cations occupying all the octahedral sites in Ax B . The value of x is (Integer answer)

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.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.In basic medium CrO2−4 oxidises S2O2−3 to form SO4 2− and itself changes into Cr (OH)−4 .The volume of 0. 154 MCrO2−4 required to react with 40 mL of 0. 25 MS2 O3 2− is _____ mL. (Rounded-off to the nearest integer)

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

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