Practice Questions

Q34.Given (A) n = 5, mℓ= +1 (B) n = 2, ℓ= 1, mℓ= −1, ms = −l/2 The maximum number of electron(s) in an atom that can have the quantum numbers as given in (A) and (B) are respectively: (1) 25 and 1 (2) 8 and 1 (3) 2 and 4 (4) 4 and 1

Q34.The shape of IF−6 is : (1) Trigonally distorted octahedron (2) Pyramidal (3) Octahedral (4) Square antiprism

Q34.A gaseous hydrocarbon on combustion gives 0. 72 g of water and 3. 08 g CO2 . What is the empirical formula of the hydrocarbon? (1) C6H5 (2) C7H8 (3) C2H4 (4) C3H4

Q34.The solubility order for alkali metal fluoride in water is : (1) LiF < RbF < KF < NaF (2) RbF < KF < NaF < LiF (3) LiF > NaF > KF > RbF (4) LiF < NaF < KF < RbF

Q35.Bond distance in HF is 9.17 × 10−11 m . Dipole moment of HF is 6.104 × 10−30Cm . The percentage ionic character in HF will be : (electron charge = 1.60 × 10−19C ) (1) 61.0% (2) 38.0% (3) 35.5% (4) 41.5%

Q35.The catenation tendency of C, Si and Ge is in the order Ge < Si < C. The bond energies (in kJ mol−1 ) of C −C, Si −Si and Ge −Ge bonds are respectively ; (1) 348, 297, 260 (2) 297, 348, 260 (3) 348, 260, 297 (4) 260, 297, 348

Q35.By how many folds the temperature of a gas would increase when the root mean square velocity of the gas molecules in a container of fixed volume is increased from 5 × 104 cm/s to 10 × 104 cm/s ? (1) Two (2) Three (3) Six (4) Four Q36. 1 1 H2(g) + O2(g) →H2O(l); H2(g) + O2(g) →H2O(g); Given: (I) 2 (II) 2 The molar enthalpy of ΔH∘298 K = −285.9 kJ mol−1 ΔH∘298 K = −241.8 kJ mol−1 vapourisation of water will be : (1) 241.8 kJ mol−1 (2) 22.0 kJ mol−1 (3) 44.1 kJ mol−1 (4) 527.7 kJ mol−1

Q35.Energy of an electron is given by E = −2.178 × 10−18( Z2n2 ) J. Wavelength of light required to excite an electron in a hydrogen atom from level n=1 to n=2 will be : (h = 6.62 × 10−34 Js and c = 3.0 × 108 ms−1) (1) 6.500 × 10−7 m (2) 8.500 × 10−7 m (3) 1.214 × 10−7 m (4) 2.816 × 10−7 m

Q35.Bond order normally gives idea of stability of a molecular species. All the molecules viz. H2, Li2 and B2 have the same bond order yet they are not equally stable. Their stability order is : JEE Main 2013 (22 Apr Online) JEE Main Previous Year Paper (1) H2 > B2 > Li2 (2) Li2 > H2 > B2 (3) Li2 > B2 > H2 (4) None of these

Q36. (in kJ) Li(s) →Li(g) 161 Li(g) →Li+(g) 520 1 F2( g) →F(g) 77 2 Given Reaction Energy Change Based on data provided, the (Electron gain F( g) + e−→F−(g) enthalpy) Li+(g) + F−(g) →LiF(s) −1047 Li(s) + 12 F2( g) →LiF(s) −617 value of electron gain enthalpy of fluorine would be : (1) −300 kJ mol−1 (2) −350 kJ mol−1 (3) −328 kJ mol−1 (4) −228 kJ mol−1

Q37.In which of the following sets, all the given species are isostructural ? (1) CO2, NO2, ClO2, SiO2 (2) PCl3, AlCl3, BCl3, SbCl3 (3) BF3, NF3, PF3, AlF3 (4) BF−4 , CCl4, NH+4 , PCl+4

Q37.Which of the following statements/relationships is not correct in thermodynamic changes ? (1) ΔU = 0 (isothermal reversible expansion of a (2) w = −nRT ln V2 (isothermal reversible V1 gas) expansion of an ideal gas) (3) w = nRT ln V2 (isothermal reversible (4) For a system of constant volume heat involved V1 expansion of an ideal gas) directly changes to internal energy.

Q37.Which of the following represents the correct order of increasing first ionization enthalpy for Ca, Ba, S, Se and Ar ? (1) Ba < Ca < Se < S < Ar (2) Ca < Ba < S < Se < Ar (3) Ca < S < Ba < Se < Ar (4) S < Se < Ca < Ba < Ar

Q37.In reaction A + 2 B ⇌2C + D, initial concentration of B was 1.5 times of [A], but at equilibrium the concentrations of A and B became equal. The equilibrium constant for the reaction is : (1) 8 (2) 4 (3) 12 (4) 6

Q38.(1) N2( g) + 3H2( g) ⇌2NH3( g), K1 (2) N2( g) + O2( g) ⇌2NO(g), K2 (3) H2( g) + 12 O2( g) ⇌H2O(g), K3 The equation for the equilibrium constant of the reaction 5 2NH3( g) + O2( g) ⇌2NO(g) + 3H2O(g), 2 (K4) in terms of K1, K2 and K3 is : (1) K1⋅K2 (2) K1⋅K23 K3 K2 3 (3) K1 K2 K3 (4) K2⋅K3 K1

Q38.Stability of the species Li2, Li−2 and Li+2 increases in the order of (1) Li2 < Li−2 < Li+2 (2) Li−2 < Li2 < Li+2 (3) Li2 < Li+2 < Li−2 (4) Li−2 < Li+2 < Li2

Q38.Solid Ba(NO3)2 is gradually dissolved in a 1.0 × 10−4 M Na2CO3 solution. At which concentration of Ba2+ , precipitate of BaCO3 begins to form ? (Ksp for BaCO3 = 5.1 × 10−9) (1) 5.1 × 10−5M (2) 7.1 × 10−8M (3) 4.1 × 10−5M (4) 8.1 × 10−7M

Q39.The structure of which of the following chloro species can be explained on the basis of dsp2 hybridization? (1) PdCl2−4 (2) FeCl2−4 (3) CoCl2−4 (4) NiCl2−4

Q39.Given : XNa2HAsO3 + YNaBrO3 + ZHCl →NaBr + H3AsO4 + NaCl The values of X, Y and Z in the above redox reaction are respectively : (1) 2, 1, 2 (2) 2, 1, 3 (3) 3, 1, 6 (4) 3, 1, 4

Q40.In which of the following pairs of molecules/ions, both the species are not likely to exist? (1) H2+2 , He2 (2) H−2 , He2+2 (3) H+2 , He2−2 (4) H−2 , He2−2 ¯

Q40.Sodium Carbonate cannot be used in place of (NH4)2CO3 for the identification of Ca2+, Ba2+ and Sr2+ ions (in group V ) during mixture analysis because : (1) Mg2+ ions will also be precipitated. (2) Concentration of CO32− ions is very low. (3) Sodium ions will react with acid radicals. (4) Na+ ions will interfere with the detection of Ca2+, Ba2+, Sr2+ ions.

Q40. Acid Ka HCN 6.2 × 10−10 Values of dissociation constant, Ka are given as follows : Correct order of increasing HF 7.2 × 10−4 HNO2 4.0 × 10−4 base strength of the base CN−, F− and NO−2 will be : (1) F−< CN−< NO−2 (2) NO−2 < CN−< F− (3) F−< NO−2 < CN− (4) NO−2 < F−< CN−

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

Q41.Equimolar solutions of the following compounds are prepared separately in water. Which will have the lowest pH value ? (1) BeCl2 (2) SrCl2 (3) CaCl2 (4) MgCl2

Q41.Which one of the following is most stable ? JEE Main 2013 (09 Apr Online) JEE Main Previous Year Paper (1) (2) (3) (4)