Practice Questions

Q36.In aqueous solution the ionization constants for carbonic acid are K1 = 4.2 × 10−7 and K2 = 4.8 × 10−11 Select the correct statement for a saturated 0.034M solution of the carbonic acid. (1) The concentration of CO2−3 is 0.034M. (2) The concentration of CO2−3 is greater than that of HCO−3 . (3) The concentration of H+ and HCO−3 are (4) The concentration of H+ is double that of CO2−3 . approximately equal.

Q37.Solubility product of silver bromide is 5.0 × 10−13 . The quantity of potassium bromide (molar mass precipitation of AgBr is (1) 1.2 × 10−10 g (2) 1.2 × 10−9 g (3) 6.2 × 10−5 g (4) 5.0 × 10−8 g

Q38.At 25∘C, the solubility product of Mg(OH)2 is 1.0 × 10−11 . At which pH, will Mg2+ ions start precipitating in the form of Mg(OH)2 from a solution of 0.001MMg2+ ions ? (1) 9 (2) 10 (3) 11 (4) 8 Q39. 29.5mg of an organic compound containing nitrogen was digested according to Kjeldahl's method and the evolved ammonia was absorbed in 20 mL of 0.1MHCl solution. The excess of the acid required 15 mL of 0.1MNaOH solution for complete neutralization. The percentage of nitrogen in the compound is (1) 59.0 (2) 47.4 (3) 23.7 (4) 29.5

Q40.The correct order of increasing basicity of the given conjugate bases (R = CH3) is –––––– (1) RCOO < HC = C < R < NH2 (2) R < HC ≡C < RCOO < NH2 ––––– (3) RCOO < NH2 < HC ≡C < R (4) RCOO < HC ≡C < NH2 < R

Q41.Out of the following, the alkene that exhibits optical isomerism is (1) 3-methyl-2-pentene (2) 4-methyl-1-pentene (3) 3-methyl-1-pentene (4) 2-methyl-2-pentene JEE Main 2010 JEE Main Previous Year Paper ⟶ ?

Q42.The main product of the following reaction is C6H5CH2CH(OH)CH(CH3)2 conc. H2SO4 (1) (2) (3) (4)

Q43.The edge length of a face centered cubic cell of an ionic substance is 508pm. If the radius of the cation is 110pm, the radius of the anion is (1) 288pm (2) 398pm (3) 618pm (4) 144pm

Q44.Percentage of free space in cubic close packed structure and in body centred packed structure are respectively (1) 30% and 26% (2) 26% and 32% (3) 32% and 48% (4) 48% and 26%

Q45.If 10−4dm3 of water is introduced into a 1.0dm3 flask to 300 K, how many moles of water are in the vapour phase when equilibrium is established? (Given : Vapour pressure of H2O at 300 K is 3170 Pa; R = 8.314 J K−1 mol−1 ) (1) 5.56 × 10−3 mol (2) 1.53 × 10−2 mol (3) 4.46 × 10−2 mol (4) 1.27 × 10−3 mol

Q46.If sodium sulphate is considered to be completely dissociated into cations and anions in aqueous solution, the change in freezing point of water (ΔTf), when 0.01 mol of sodium sulphate is dissolved in 1 kg of water, is (Kf = 1.86 K kg mol−1) (1) 0.0372 K (2) 0.0558 K (3) 0.0744 K (4) 0.0186 K

Q47.On mixing, heptane and octane form an ideal solution. At 373 K, the vapour pressures of the two liquid components (heptane and octane) are 105kPa and 45kPa respectively. Vapour pressure of the solution obtained by mixing 25.0 g of heptane and 35 g of octane will be (molar mass of heptane = 100 g mol−1 an dof octane = 114 g mol−1 ). (1) 72.0kPa (2) 36.1kPa (3) 96.2kPa (4) 144.5kPa

Q48.The Gibbs energy for the decomposition of Al2O3 at 500∘C is as follows : 2 Al2O3 →4 Al + O2, ΔrG = +966 kJ mol−1 3 3 The potential difference needed for electrolytic reduction of Al2O3 at 500∘C is at least (1) 4.5 V (2) 3.0 V (3) 2.5 V (4) 5.0 V JEE Main 2010 JEE Main Previous Year Paper

Q49.The correct order of E0 values with negative sign for the four successive elements Cr, Mn, Fe and Co is SR2/M (1) Mn > Cr > Fe > Co (2) Cr > Fe > Mn > Co (3) Fe > Mn > Cr > Co (4) Cr > Mn > Fe > Co

Q50.The time for half life period of a certain reaction A → products is 1 hour. When the initial concentration of the reactant ' A ', is 2.0 mol L−1 , how much time does it take for its concentration to come from 0.50 to 0.25 mol L−1 if it is a zero order reaction? (1) 4 h (2) 0.5 h (3) 0.25 h (4) 1 h

Q51.Consider the reaction : Cl2(aq) + H2 S(aq) →S(s) + 2H+(aq) + 2Cl−(aq) The rate equation for this reaction is rate = k [Cl2] [H2 S] Which of these mechanisms is/are consistent with this rate equation? (A) Cl2 + H2 →H+ + Cl−+ Cl+ + HS− (slow) Cl+ + HS−→H+ + Cl−+ S (fast) (B) H2 S ⇔H+ + HS− (fast equilibrium) Cl2 + HS−→2Cl−+ H+ + S (slow) (1) B only (2) Both A and B (3) Neither A nor B (4) A only

Q52.Three reactions involving H2PO−4 are given below : (i) H3PO4 + H2O →H3O+ + H2PO−4 (ii) H2PO−4 + H2O →HPO2−4 + H3O+ (iii) H2PO−4 + OH−→H3PO4 + O2− In which of the above does H2PO−4 act as an acid ? (1) (ii) only (2) (i) and (ii) (3) (iii) only (4) (i) only

Q53.A solution containing 2.675 g of CoCl3.6NH3 (molar mass = 267.5 g mol−1 ) is passed through a cation exchanger. The chloride ions obtained in solution were treated with excess of AgNO3 to give 4.78 g of AgCl (molar mass = 143.5 g mol−1 ). The formula of the complex is (At. Mass of Ag = 108u ) (1) [Co(NH3)6]Cl3 (2) [CoCl2(NH3)4]Cl (3) [CoCl3(NH3)3] (4) [CoCl(NH3)5]Cl2

Q54.Which one of the following has an optical isomer ? (en = ethylenediamine) (1) [Zn(en)(NH3)2]2+ (2) [Co(en)3]3+ (3) [Co(H2O)4( en )]3+ (4) [Zn( en )2]2+

Q55. Consider the following bromides : The correct order of SN1 reactivity is JEE Main 2010 JEE Main Previous Year Paper (1) B > C > A (2) B > A > C (3) C > B > A (4) A > B > C

Q56.From amongst the following alcohols the one that would react fastest with conc. HCl and anhydrous ZnCl2 , is (1) 2-Butanol (2) 2-Methylpropan-2-ol (3) 2-Methylpropanol (4) 1-Butanol

Q57.One mole of a symmetrical alkene on ozonolysis gives two moles of an aldehyde having a molecular mass of 44u. The alkene is (1) propene (2) 1-butene (3) 2-butene (4) ethene

Q58. In the chemical reactions, the compounds ' A ' and ' B ' respectively are (1) nitrobenzene and fluorobenzene (2) phenol and benzene (3) benzene diazonium chloride and fluorobenzene (4) nitrobenzene and chlorobenzene

Q59.The polymer containing strong intermolecular forces e.g. hydrogen bonding, is (1) teflon (2) nylon 6,6 (3) polystyrene (4) natural rubber

Q60.Biuret test is not given by (1) carbohydrates (2) polypeptides (3) urea (4) proteins

Q61.If α and β are the roots of the equation x2 −x + 1 = 0, then α2009 + β2009 = (1) −1 (2) 1 (3) 2 (4) −2