Practice Questions

Q41.In which of the following exothermic reactions, the heat liberated per mole is the highest ? (1) CaO + H2O →Ca(OH)2 (2) SrO + H2O →Sr(OH)2 (3) BaO + H2O →Ba(OH)2 (4) MgO + H2O →Mg(OH)2

Q42.A piston filled with 0.04 mol of an ideal gas expands reversibly from 50.0 mL to 375 mL at a constant temperature of 37. 0∘C. As it does so, it absorbs 208 J of heat. The values of q and w for the process will be (R = 8.314 J/mol K) (ln7.5 = 2.01) (1) q = −208 J, w = +208 J (2) q = +208 J, w = +208 J (3) q = +208 J, w = −208 J (4) q = −208 J, w = −208 J

Q42.Rate of dehydration of alcohols follows the order: (1) 2∘> 1∘> CH3OH > 3∘ (2) 3∘> 2∘> 1∘> CH3OH (3) 2∘> 3∘> 1∘> CH3OH (4) CH3OH > 1∘> 2∘> 3∘

Q43.A major component of Borsch reagent is obtained by reacting hydrazine hydrate with which of the following ? JEE Main 2013 (22 Apr Online) JEE Main Previous Year Paper (1) (2) (3) (4)

Q43.In a face centred cubic lattice, atoms of A form the corner points and atoms of B form the face centred points. If two atoms of A are missing from the corner points, the formula of the ionic compound is : (1) AB3 (2) AB4 (3) A2 B5 (4) AB2

Q43.Consider the following reaction: x MnO−4 + y C2O2−4 + zH+ ⟶x Mn2+ + 2y CO2 + 2z H2O The values of x, y and z in the reaction are, respectively: (1) 2, 5 and 16 (2) 5, 2 and 8 (3) 5, 2 and 16 (4) 2, 5 and 8

Q44.The addition of HI in the presence of peroxide catalyst does not follow anti-Markovnikov's rule because : (1) HI is a strong reducing agent. (2) H −I bond is too strong to be broken homolytically. (3) I atom combines with H atom to give back HI. (4) Iodine atom is not reactive enough to add across a double bond.

Q44.What would be the pH of a solution obtained by mixing 5 g of acetic acid and 7.5 g of sodium acetate and making the volume equal to 500 mL ? (Ka = 1.75 × 10−5, pKa = 4.76) (1) pH = 4.70 (2) pH < 4.70 (3) pH of solution will be equal to pH of acetic acid (4) 4.76 < pH < 5.0

Q44.A solution of (−)1 −chloro −1 −phenylethane in toluene racemises slowly in the presence of a small amount of SbCl5, due to the formation of : (1) Carbocation (2) Free radical (3) Carbanion (4) Carbene JEE Main 2013 (07 Apr) JEE Main Previous Year Paper

Q44.Vapour pressure of pure benzene is 119 torr and that of toluene is 37.0 torr at the same temperature. Mole fraction of toluene in vapour phase which is in equilibrium with a solution of benzene and toluene having a mole fraction of toluene 0.50, will be : (1) 0.137 (2) 0.237 (3) 0.435 (4) 0.205

Q45.Which one of the following arrangements represents the correct order of the proton affinity of the given species : (1) I−< F−< HS−< NH−2 (2) HS−< NH−2 < F−< I− (3) F−< I−< NH−2 < HS− (4) NH−2 < HS−< I−< F−

Q45.Arrange the following compounds in order of decreasing acidity : (1) III > I > II > IV (2) IV > III > I > II (3) II > IV > I > III (4) I > II > III > IV

Q45.An element having an atomic radius of 0.14 nm crystallizes in an fcc unit cell. What is the length of a side of the cell ? (1) 0.56 nm (2) 0.24 nm (3) 0.96 nm (4) 0.4 nm Q46. 12 g of a nonvolatile solute dissolved in 108 g of water produces the relative lowering of vapour pressure of 0.1. The molecular mass of the solute is : (1) 80 (2) 60 (3) 20 (4) 40

Q45.Given : Eo1 1.36 V, Eo = −0.74 V 2 Cl2/Cl−= Cr3+/Cr Eo = 1.33 V, Eo = 1.51 V Cr2O2−7 /Cr3+ MnO−4 /Mn2+ The correct order of reducing power of the species (Cr, Cr3+, Mn2+ and Cl−)will be: (1) Mn2+ < Cl−< Cr3+ < Cr (2) Mn2+ < Cl3+ < Cl−< Cr (3) Cr3+ < Cl−< Mn2+ < Cr (4) Cr3+ < Cl−< Cr < Mn2+

Q45.Which of the following would not give 2-phenylbutane as the major product in a Friedel-Crafts alkylation reaction ? (1) 1-butene +HF (2) 2-butanol +H2SO4 (3) Butanoyl chloride +AlCl3 then Zn, HCl (4) Butyl choloride +AlCl3

Q46.The order of stability of the following carbocations: (1) I > II > III (2) III > I > II (3) III > II > I (4) II > III > I

Q47.A molecule M associates in a given solvent according to the equation M ⇌(M)n . For a certain concentration of M, the van't Hoff factor was found to be 0.9 and the fraction of associated molecules was 0.2. The value of n is: (1) 3 (2) 5 (3) 2 (4) 4

Q47.Copper crystallises in fcc with a unit length of 361 pm . What is the radius of copper atom ? (1) 157 pm (2) 128 pm (3) 108 pm (4) 181 pm

Q48.The instantaneous rate of disappearance of MnO−4 ion in the following reaction is 4.56 × 10−3Ms−1 2MnO−4 + 10I−+ 16H+ →2Mn2+ + 5I2 + 8H2O The rate of appearance I2 is : (1) 4.56 × 10−4Ms−1 (2) 1.14 × 10−2Ms−1 (3) 1.14 × 10−3Ms−1 (4) 5.7 × 10−3Ms−1

Q48.Which has trigonal bipyramidal shape ? (1) XeOF4 (2) XeO3 (3) XeO3 F2 (4) XeOF2

Q48.Flocculation value of BaCl2 is much less than that of KCl for sol A and flocculation value of Na2SO4 is much less than that of NaBr for sol B. The correct statement among the following is : (1) Both the sols A and B are negatively charged. (2) Sol A is positively charged and Sol B is negatively charged. (3) Both the sols A and B are positively charged. (4) Sol A is negatively charged and sol B is positively charged.

Q48.The Gibbs energy for the decomposition of Al2O3 at 500 C is as follows : 2 3 Al2O3 →43 Al + O2, ΔrG = +940 kJ mol−1 The potential difference needed for the electrolytic reduction of aluminium oxide at 500∘C should be at least : JEE Main 2013 (25 Apr Online) JEE Main Previous Year Paper (1) 4.5 V (2) 3.0 V (3) 5.0 V (4) 2.5 V

Q49.Four successive members of the first row of transition elements are listed below with atomic numbers. Which one of them is expected to have the highest Eo value? M3+/M2+ (1) Fe (Z = 26) (2) Co (Z = 27) (3) Cr (Z = 24) (4) Mn (Z = 25)

Q49.When a small amount of KMnO4 is added to concentrated H2SO4 , a green oily compound is obtained which is highly explosive in nature. Compound may be : (1) MnSO4 (2) Mn2O7 (3) MnO2 (4) Mn2O3 JEE Main 2013 (23 Apr Online) JEE Main Previous Year Paper

Q50.Identify incorrect statement : (1) Cu2O is colourless. (2) Copper (I) compounds are colourless except when colour results from charge transfer. (3) Copper (I) compounds are diamagnetic. (4) Cu2 S is black.