Practice Questions

Q32.How many litres of water must be added to 1 litre of aqueous solution of HCl with a pH of 1 to create an aqueous solution with pH of 2 ? (1) 2. 0 (2) 9. 0 (3) 0. 1 (4) 0. 9

Q32.The wave number of the first emission line in the Balmer series of H -Spectrum is : (R = Rydberg constant ) : (1) 5 R (2) 9 R 36 400 (3) 7 R (4) 3 R 6 4

Q32.How many grams of methyl alcohol should be added to 10 litre tank of water to prevent its freezing at 268 K ? ( Kf for water is 1.86 K kg mol−1) (1) 880.07 g (2) 899.04 g (3) 886.02 g (4) 868.06 g Q33. 10 mL of 2(M) NaOH solution is added to 200 mL of 0.5 (M) of NaOH solution. What is the final concentration ? (1) 0.57(M) (2) 5.7(M) (3) 11.4(M) (4) 1.14(M)

Q32.The de Broglie wavelength of a car of mass 1000 kg and velocity 36 km/hr is : JEE Main 2013 (23 Apr Online) JEE Main Previous Year Paper (1) 6.626 × 10−34 m (2) 6.626 × 10−38 m (3) 6.626 × 10−31 m (4) 6.626 × 10−30 m

Q32.Electron gain enthalpy with negative sign of fluorine is less than that of chlorine due to : (1) High ionization enthalpy of fluorine (2) Smaller size of chlorine atom (3) Smaller size of fluorine atom (4) Bigger size of 2p orbital of fluorine

Q33.Which one of the following molecules is polar? (1) XeF4 (2) IF5 (3) SbF5 (4) CF4

Q33.Experimentally it was found that a metal oxide has formula M0.98O. Metal M, is present as M2+ and M3+ in its oxide. Fraction of the metal which exists as M3+ would be: (1) 6. 05% (2) 5. 08% (3) 7. 01% (4) 4. 08%

Q33.The order of increasing sizes of atomic radii among the elements O, S, Se and As is : (1) As < S < O < Se (2) Se < S < As < O (3) O < S < As < Se (4) O < S < Se < As

Q33.Which is the correct order of second ionization potential of C, N, O and F in the following ? (1) O > N > F > C (2) O > F > N > C (3) F > O > N > C (4) C > N > O > F

Q34.In which of the following ionization processes the bond energy has increased and also the magnetic behaviour has changed from paramagnetic to diamagnetic ? (1) NO →NO+ (2) N2 →N+2 (3) C2 →C+2 (4) O2 →O+2 JEE Main 2013 (09 Apr Online) JEE Main Previous Year Paper

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.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 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

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

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.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.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.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

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%

Q36.The first ionisation potential of Na is 5.1 eV. The value of electron gain enthalpy of Na + will be : (1) -10.2 eV (2) +2.55 eV (3) -2.55 eV (4) -5.1 eV JEE Main 2013 (07 Apr) JEE Main Previous Year Paper

Q36.Which one of the following cannot function as an oxidising agent? (1) I− (2) S(s) (3) NO−3 (aq) (4) Cr2O2−7

Q36.The correct order of viscosity of the following liquids will be : (1) Water < methyl alcohol < dimethyl ether < glycerol (2) methyl alcohol < glycerol < water < dimethyl ether (3) dimethyl ether < methyl alcohol < water < glycerol (4) glycerol < dimethyl ether < water < methyl alcohol

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 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

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