Practice Questions

Q49.How long (approximate) should water be electrolysed by passing through 100 amperes current so that the oxygen released can completely burn 27. 66 g of diborane? (Atomic weight of B = 10. 8 u) (1) 1. 6 hours (2) 6. 4 hours (3) 0. 8 hours (4) 3. 2 hours

Q49.When XO2 is fused with an alkali metal hydroxide in presence of an oxidizing agent such as KNO3 ; a dark green product is formed which disproportionate in acidic solution to afford a dark purple solution. X is: JEE Main 2018 (16 Apr Online) JEE Main Previous Year Paper (1) Mn (2) Cr (3) V (4) Ti

Q49. N2O5 decomposes to NO2 and O2 follows the first order kinetics. After 50 minutes, the pressure inside the vessel increases from 50 mm Hg to 87. 5 mm Hg . The pressure of the gaseous mixture after 100 minutes at constant temperature will be: (1) 136. 5 mm Hg (2) 106. 25 mm Hg (3) 175. 0 mm Hg (4) 116. 25 mm Hg

Q52. N2O5 decomposes to NO2 and O2 and follows first order kinetics. After 50 minutes, the pressure inside the vessel increases from 50 mm Hg to 87.5 mm Hg . The pressure of the gaseous mixture after 100 minutes at constant temperature will be ______. (1) 136.25 mm Hg (2) 106.25 mm Hg (3) 175.0 mm Hg (4) 116.25 mm Hg

Q52.Consider the following reaction and statements: [Co (NH3)4 Br2]+ + Br−→[Co (NH3)3 Br3] + NH3 (i) Two isomers are produced if the reactant complex ion is a cis-isomer. (ii) Two isomers are produced if the reactant complex ion is a trans-isomer. (iii) Only one isomer is produced if the reactant complex ion is a trans-isomer. (iv) Only one isomer is produced if the reactant complex ion is a cis-isomer. The correct statements are (1) (ii) and (iv) (2) (i) and (ii) (3) (i) and (iii) (4) (iii) and (iv)

Q53.The correct combination is (1) [NiCl4]2−− Square planar; [Ni (CN)4]2−− (2) [Ni (CN)4]2−− tetrahedral; [Ni (CO)4]2−− paramagnetic paramagnetic (3) [NiCl4]2−− paramagnetic; [Ni (CO)4]− (4) [NiCl4]2−− diamagnetic; [Ni (CO)4]− square- tetrahedral planar

Q54.The major product of the following reaction is: JEE Main 2018 (16 Apr Online) JEE Main Previous Year Paper (1) (2) (3) (4)

Q55.The total number of possible isomers for squareplanar [Pt(Cl) (NO2) (NO3)(SCN)]2− is: (1) 16 (2) 12 (3) 8 (4) 24

Q57.The reagent(s) required for the following conversion are: (1) (i) NaBH4 , (ii) Raney Ni/H2 , (iii) H3O+ (2) (i) LiAlH4 , (ii) H3O+ (3) (i) B2H6 , (ii) DIBAL −H, (iii) H3O+ (4) (i) B2H6 , (ii) SnCl2/HCl, (iii) H3O+

Q44.The freezing point of benzene decreases by 0.45°C on adding 0 . 2 g of acetic acid to 20 g of benzene. If acetic acid associates to form a dimer in benzene, then what is the percentage association of acetic acid in benzene? Kf for benzene = 5 .12 K kg mol-1 (1) 80 . 4% (2) 74 . 6% (3) 94 . 6% (4) 64 . 6%

Q53.The major product obtained in the following reaction is, (1) C6H5CH = CHC6H5 (2) + C6H5CHOtBuCH2C6H5 (3) - C6H5CHOtBuCH2C6H5 (4) ± C6H5CHOtBuCH2C6H5

Q58.Among the following compounds, the increasing order of their basic strength is: (1) (II) < (I) < (III) < (IV) (2) (II) < (I) < (IV) < (III) (3) (I) < (II) < (IV) < (III) (4) (I) < (II) < (III) < (IV)

Q34.The group of molecules having identical shape is: (1) PCl5, IF5, XeO2F2 (2) BF3, PCl3, XeO3 (3) SF4, XeF4, CCl4 (4) ClF3, XeOF2, XeF+3

Q50.The plot shows the variation of −ln KP Versus temperature for the two reactions. M(s) + 12 O2(g) →MO(s) and C(s) + 12 O2(g) →CO(s) Identify the correct statement: (1) At T < 1200 K, oxidation of carbon is (2) Oxidation of carbon is favourable at all unfavourable temperatures (3) At T < 1200 K, the reaction (4) At T > 1200 K, carbon will reduce MO(s) + C(s) →M(s) + CO(g) is spontaneous MO(s) to M(s) .

Q56.The correct statement about the synthesis of erythritol (C(CH2OH)4) used in the preparation of PETN is (1) The synthesis requires three aldol condensations (2) Alpha hydrogen of ethanol and methanol are and one Cannizzaro reaction. involved in this reaction. (3) The synthesis requires two aldol condensation (4) The synthesis requires four aldol condensations and two Cannizzaro reactions. between methanol and ethanol.

Q34.At temperature T , the average kinetic energy of any particle is 32 kT. The de Broglie wavelength follows the order: (1) Visible photon >thermal electron >thermal (2) Thermal neutron >visible photon >thermal neutron. electron. (3) Thermal neutron >thermal electron >visible (4) Visible photon >thermal neutron >thermal photon. electron.

Q37.The heat of atomization of methane and ethane are 360 kJ mol−1 and 620 kJ mol−1 , respectively. The longest wavelength of light capable of breaking the C −C bond is (Avogadro's number = 6.023 × 1023, h = 6.62 × 10−34 J s) (1) 2.48 × 104 nm (2) 1.49 × 104 nm (3) 2.48 × 103 nm (4) 1.49 × 103 nm

Q44.Photochemical smog consists of excessive amount of X, in addition to aldehydes, ketones, peroxy acetyl nitrile (PAN). X is: (1) CH4 (2) CO2 (3) O3 (4) CO

Q51.Which one of the following compounds is not a yellow colored compound ? (1) BaCrO4 (2) Zn2[Fe(CN)6] (3) K3[Co(NO2)6] (4) (NH4)3[As (Mo3O10)4]

Q54.The correct statement on the isomerism associated with the following complex ions. (a) [Ni(H2O)5NH3]2+ (b) [Ni(H2O)4(NH3)2]2+ and (c) [Ni(H2O)3(NH3)3]2+ is: (1) (a) and (b) show only geometrical isomerism (2) (a) and (b) show geometrical and optical isomerism (3) (b) and (c) show geometrical and optical (4) (b) and (c) show only geometrical isomerism isomerism

Q36.Which one of the following does not have a pyramidal shape? (1) (CH3)3 N (2) (SiH3)3 N (3) P(CH3)3 (4) P(SiH3)3

Q39.The standard enthalpy of formation (ΔfH∘298) for methane, CH4 is −74.9 kJ mol−1 . In order to calculate the average energy given out in the formation of a C −H bond from this it is necessary to know which one of the following? (1) The dissociation energy of the hydrogen (2) The first four ionisation energies of carbon. molecule, H2 . (3) The dissociation energy of H2 and enthalpy and (4) The first four ionisation energies of carbon and sublimation of carbon (graphite). electron affinity of hydrogen.

Q45.In the presence of peroxide, HCl and HI do not give anti-Markownikoff's addition of alkenes because: (1) One of the steps is endothermic in HCl and HI (2) Both HCl and HI are strong acids (3) HCl is oxidizing and the HI is reducing (4) All the steps are exothermic is HCl and HI

Q51.The equation which is balanced and represents the correct product(s) is (1) Li2O + 2KCl →2LiCl + K2O (2) [CoCl (NH3)5]+ + 5H+ →Co2+ + 5 NH+4 + Cl− (3)− [Mg (H2O)6]2+ + (EDTA)4−excess NaOH→ [Mg(EDTA)]2+(4) CuSO4+ +6H2O4KCN →K2[Cu (CN)4] + K2 SO4

Q58.An organic compound A, C5H8O; reacts with H2O, NH3 and CH3COOH as described below: (1) (2) (3) (4)