Practice Questions

Q32.If the shortest wavelength in Lyman series of hydrogen atom is A, then the longest wavelength in Paschen series of He+ is (1) 5A (2) 36A 9 7 (3) 36A (4) 9A 5 5

Q32.The most abundant elements by mass in the body of a healthy human adult are: Oxygen (61.4%); Carbon (22.9%), Hydrogen (10.0%); and Nitrogen (2.6%). The weight which a 75kg person JEE Main 2017 (02 Apr) JEE Main Previous Year Paper would gain if all 1𝐻 atoms are replaced by 2𝐻 atoms is: (1) 37.5 kg (2) 7.5 kg (3) 10 kg (4) 15 kg

Q32.The electron in the hydrogen atom undergoes transition from higher orbitals to orbital of radius 211. 6 pm . This transition is associated with (1) Lyman series (2) Balmer series (3) Brackett series (4) Paschen series

Q33.The electronic configuration with the highest ionization enthalpy is: (1) [Ar] 3d10 4s2 4p3 (2) [Ne]3s2 3p1 (3) [Ne] 3s2 3p3 (4) [Ne] 3s2 3p2

Q33.Which of the following is paramagnetic? (1) CO (2) NO+ (3) O2−2 (4) B2

Q34. sp3 d2 hybridization is not displayed by (1) SF6 (2) BrF5 (3) PF5 (4) [CrF6]3−

Q34.The radius of the second Bohr orbit for hydrogen atom is (Planck's constant, ( h ) = 6 .6262 × 10−34Js; mass of electron = 9 .1091 × 10-31kg; charge of electron = 1 .60210 × 10-19C; permittivity of vacuum, ( ∈0 ) = 8 .854185 × 10-12kg-1m-3A2) (1) 4 .76 Å (2) 0 .529 Å (3) 2 .12 Å (4) 1 .65 Å

Q34.The group having triangular planar structure is: (1) BF3, NF3, CO2−3 (2) CO2−3 , NO−3 , SO3 (3) NH3, SO3, CO2−3 (4) NCl3, BCl3, SO3

Q35.Which of the following species is not paramagnetic? (1) CO (2) O2 (3) B2 (4) NO

Q35.Among the following, the incorrect statement is: (1) at low pressure, real gases show ideal behaviour. (2) at very low temperature, real gases show ideal behaviour. (3) at Boyle's temperature, real gases show ideal (4) at very large volume, real gases show ideal behaviour. behaviour.

Q35.The increasing order of the boiling points for the following compounds is: (I)C2H5 OH (II)C2H5 Cl (III)C2H5 CH3 (IV) C2H5 OCH3 (1) (IV) < (III) < (I) < (II) (2) (III) < (II) < (I) < (IV) (3) (III) < (IV) < (II) < (I) (4) (II) < (III) < (IV) < (I) JEE Main 2017 (09 Apr Online) JEE Main Previous Year Paper

Q36.The enthalpy change on freezing of 1 mol of water at 5°C to ice at −5°C is: (Given Δfus H = 6 kJ mol−1 at 0°C, Cp(H2O, l) = 75 .3 J mol−1 K−1 Cp(H2O, s) = 36 .8 J mol−1 K−1 ) (1) 6 .00 kJ mol−1 (2) 5 .81 kJ mol−1 (3) 5 .44 kJ mol−1 (4) 6 .56 kJ mol−1

Q36.Among the following compounds, the compound which shows the highest dipole-moment is (1) (II) (2) (IV) (3) (III) (4) (I)

Q36.Given: Cgraphite + O2g →CO2g ; ΔrHo = −393 .5 kJ mol−1 1 H2g + 2O2g →H2Ol; ΔrHo = - 285 .8 kJ mol-1 CO2g + 2H2Ol →CH4g + 2O2g; ΔrHo = + 890 .3 kJ mol-1 Based on the above thermochemical equations, the value of ΔrHo at 298 K for the reaction Cgraphite + 2H2g →CH4g will be: (1) +144 .0 kJ mol-1 (2) -74 .8 kJ mol-1 (3) -144 .0 kJ mol-1 (4) +74 .8 kJ mol-1 Q37.ΔU is equal to: (1) Isobaric work (2) Adiabatic work (3) Isothermal work (4) Isochoric work

Q37.At 300 K, the density of a certain gaseous molecule at 2 bar is double to that of dinitrogen (N2) at 4 bar. The molar mass of the gaseous molecule is (1) 224 g mol−1 (2) 112 g mol−1 (3) 56 g mol−1 (4) 28 g mol−1

Q37.For a reaction, A(g) →A(l); ΔH = −3 RT. The correct statement for the reaction is (1) ΔH = ΔU = O (2) |ΔH| < |ΔU| (3) |ΔH| > |ΔU| (4) ΔH = ΔU ≠O

Q38.pKa of a weak acid HA and pKb of a weak base BOH are 3.2 and 3.4 respectively. The pH of their salt AB solution at 25oC is (1) 6.9 (2) 7.0 (3) 1.0 (4) 7.2

Q38.An ideal gas undergoes isothermal expansion at constant pressure. During the process: (1) Enthalpy remains constant but entropy increases (2) Enthalpy decreases but entropy increases (3) Enthalpy increases but entropy decreases (4) Both enthalpy and entropy remain constant

Q38.Addition of sodium hydroxide solution to a weak acid (HA) results in a buffer of pH 6. If ionization constant of HA is 10−5 , the ratio of salt to acid concentration in the buffer solution will be: (1) 10 : 1 (2) 4 : 5 (3) 5 : 4 (4) 1 : 10

Q39.Both lithium and magnesium display several similar properties due to the diagonal relationship; however, the one which is incorrect is: (1) Both form soluble bicarbonates (2) Both form nitrides (3) Nitrates of both Li and Mg yield NO2 and O2 on (4) Both form basic carbonate heating

Q39.A gas undergoes change from state A to state B. In this process, the heat absorbed and work done by the gas is 5 J and 8 J, respectively. Now gas is brought back to A by another process during which 3 J of heat is evolved. In this reverse process of B to A. (1) 6 J of the work will be done by the gas (2) 6 J of the work will be done by the surroundings on gas (3) 10 J of the work will be done by the surroundings (4) 10 J of the work will be done by the gas on gas

Q39.The pair of compounds having metals in their highest oxidation state is (1) Mn2 O7 and CrO2 Cl2. (2) [Fe (CN)6]3− and [Cu (CN)4]2−. (3) [NiCl4]2− and [CoCl4]2−. (4) [FeCl4]− and Co2 O3.

Q40.Which of the following molecules is least resonance stabilized? JEE Main 2017 (02 Apr) JEE Main Previous Year Paper (1) (2) (3) (4)

Q40.In which of the following reactions, hydrogen peroxide acts as an oxidizing agent? (1) HOCl + H2O2 →H3O+ + Cl−+ O2 (2) I2 + H2O2 + 2OH−→2I−+ 2H2O + O2 (3) PbS + 4H2O2 →PbSO4 + 4H2O (4) 2MnO−4 + 3H2O2 →2MnO2 + 3O2 + 2H2O + 2OH−

Q41.Which of the following compounds will form significant amount of meta product during mono-nitration reaction? (1) (2) (3) (4)