Practice Questions

Q33.Two pi and half sigma bonds are present in: (1) O−2 (2) N 2+ (3) N2 (4) O2

Q33.The correct order of the first ionization enthalpies is: (1) Ti < Mn < Zn < Ni (2) Ti < Mn < Ni < Zn (3) Mn < Ti < Zn < Ni (4) Zn < Ni < Mn < Ti JEE Main 2019 (10 Apr Shift 2) JEE Main Previous Year Paper

Q33.The element having the greatest difference between its first and second ionization energies, is (1) Ba (2) K (3) Ca (4) Sc

Q33.In comparison to boron, berylium has: (1) greater nuclear charge and lesser first ionisation enthalpy (2) lesser nuclear charge and greater first ionisation enthalpy (3) lesser nuclear charge and lesser first ionisation enthalpy. (4) greater nuclear charge and greater first ionisation enthalpy.

Q34.For silver, Cp (JK-1mol-1 ) = 23 + 0.01T . If the temperature T of 3 moles of silver is raised from 300 K to 1000 K at 1 atm pressure, the value of ΔH will be close to: JEE Main 2019 (08 Apr Shift 1) JEE Main Previous Year Paper (1) 16 kJ (2) 62 kJ (3) 13 kJ (4) 21 kJ

Q34.Two blocks of the same metal having same mass and at temperature T1, and T2 , respectively, are brought in contact with each other and allowed to attain thermal equilibrium at constant pressure. The change in entropy, JEE Main 2019 (11 Jan Shift 1) JEE Main Previous Year Paper ΔS, for this process is : 2 (T1+T2) (1) CP ln T1T2 [ (T1+T2)24 T1 T2 ] (2) 2Cp ln [ 1 ] 2CP ln [ 2T1+T2T1 T2 ] (3) 2CP ln ( 4T1+T2T1 T2 ) (4)

Q34.An ideal gas undergoes isothermal compression from 5 m3 to 1 m3 against a constant external pressure of 4 N m−2 . The heat released in this process is 24 J mol−1 K−1 and is used to increase the pressure of 1 mole of Al. The temperature of Al increases by: (1) 2 K (2) 1 K 3 (3) 3 2 K (4) 2 K Q35. 5 .1 g NH4 SH is introduced in 3 .0 L evacuated flask at 327oC . 30% of the solid NH4 SH is decomposed to NH3 and H2S as gases. The KP of the reaction at 327oC is (R = 0 .082 L atm mol−1 K−1, Molar mass of S = 32 g mol−1, Molar mass of N = 14 g mol−1) (1) 0 .242 atm2 (2) 0 .242 ×10−4 atm2 (3) 1 × 10−4 atm2 (4) 4 .9 ×10−3 atm2

Q34.The correct order of atomic radii is: (1) Ce>Eu>Ho>N (2) N>Ce>Eu>Ho (3) Ho>N>Eu>Ce (4) Eu>Ce>Ho>N

Q34.According to molecular orbital theory, which of the following is true with respect to Li2+ and Li2- ? (1) 𝐿𝑖2+ is stable and 𝐿𝑖2- is unstable (2) Both are unstable (3) Both are stable (4) 𝐿𝑖2+ is unstable and 𝐿𝑖2- is stable Q35.0.5 moles of gas A and x moles of gas B exert a pressure of 200 Pa in a container of volume 10 m3 at 1000 K . Given, R is the gas constant in JK-1mol-1, x is: (1) 4 + R (2) 2R 2R 4 + R 4 - R 2R (3) (4) 2R 4 - R

Q34.The volume of gas A is twice than that of gas B . The compressibility factor of gas A is thrice than that of gas B at same temperature. What are the pressures of the gases for equal number of moles? (1) 2PA = 3PB (2) PA = 2PB (3) 3PA = 2PB (4) PA = 3PB

Q34.During the change of O2 to O−2 , the incoming electron goes to the orbital: (1) π 2px (2) π* 2px (3) π 2py (4) σ* 2pz

Q34.At a given temperature T, gases Ne, Ar, Xe and Kr are found to deviate from ideal gas behaviour. Their equation of state is given as p = V−bRT at T. Here, b is the van der Waals constant. Which gas will exhibit steepest increase in the plot of Z (compression factor) vs p? (1) Ne (2) Kr (3) Ar (4) Xe

Q34.The correct statement among the following is: JEE Main 2019 (12 Apr Shift 1) JEE Main Previous Year Paper (1) SiH33N is planar and less basic than CH33N (2) SiH33N is pyramidal and more basic than CH33N (3) SiH33N is pyramidal and less basic than CH33N (4) SiH33N is planar and more basic than CH33N

Q34.In which of the following processes, the bond order has increased and paramagnetic character has changed to diamagnetic? (1) O2 →O+2 (2) NO →NO+ (3) O2 →O−2 (4) N2 →N 2+

Q34.Points I, II and III in the following plot respectively correspond to (Vmp: most probable velocity) (1) Vmp of N2300 K; Vmp of H2300 K; Vmp of (2) Vmp of H2300 K; Vmp of N2300 K; Vmp of O2400 K; O2400 K; (3) Vmp of N2300 K; Vmp of O2400 K; Vmp of (4) Vmp of O2400 K; Vmp of N2300 K; Vmp of H2300 K; H2300 K;

Q34.The reaction MgO(s) + C(s) →Mg(s) + CO(g), for which ΔH∘= +491.1 kJ mol−1 and ΔS∘= 198.0JK−1 mol−1 is not feasible at 298 K. Temperature above which reaction will be feasible is (1) 2040.5 K (2) 1890.0 K (3) 2480.3 K (4) 2380.5 K

Q34.Among the following, the molecule expected to be stabilized by anion formation is: C2, O2, NO, F2 (1) F2 (2) C2 (3) O2 (4) NO

Q35.The difference between ∆H and ∆U is ∆H - ∆U, when the combustion of one mole of heptane l is carried out at a temperature T , is equal to: (1) -4RT (2) 3RT (3) 4RT (4) -3RT

Q35.For the chemical reaction X ⇌Y, the standard reaction Gibbs energy depends on temperature T (in K ) as ΔrG∘( in kJmol−1) = 120 −38 T The major component of the reaction mixture at T is : (1) Y if T = 300K (2) Y if T = 280 K (3) X if T = 350 K (4) X if T = 315K

Q35.Among the following molecules/ ions, C22 - , N22 - , O22 - , O2 Which one is diamagnetic and has the shortest bond length? (1) N22 - (2) O22 - (3) O2 (4) C22 - Q36.5 moles of an ideal gas at 100 K are allowed to undergo reversible compression till its temperature becomes 200 K . If CV = 28 J K-1, calculate ∆U and ∆pV for the process. (R = 8.0 J K-1 mol-1 ) (1) ∆U = 14 J; ∆pV = 0.8 J (2) ∆U = 14 kJ; ∆pV = 18 kJ (3) ∆U = 14 kJ; ∆pV = 4 kJ (4) ∆U = 2.8 kJ; ∆pV = 0.8 kJ

Q35.For a diatomic ideal gas in a closed system, which of the following plots does not correctly describe the relation between various thermodynamic quantities? (1) (2) (3) (4) JEE Main 2019 (12 Jan Shift 1) JEE Main Previous Year Paper

Q35.If solubility product of Zr3 ( PO4 ) 4 is denoted by Ksp and its molar solubility is denoted by S , then which of the following relation between S and Ksp is correct? (1) Ksp 16 (2) Ksp 17 (3) Ksp 19 (4) Ksp 17 S = S = S = S = 144 6912 929 216

Q35.What are the values of Kp for the following reactions at 300 K respectively? Kc (At 300 K, RT = 24 .62 dm2 atm mol−1 ) N2 (g) + O2 (g) ⇌2 NO (g) N2O4 (g) ⇌2 NO (g) N2 (g) + 3H2 (g) ⇌2 NH3 (g) (1) 24 .63 dm3 atm mol−1, (2) 1 ,24.62 dm6 atm3 mol−1 606 .0 dm6 atm2 mol−2, 606 .0 dm6 atm2 mol−2 1 .65 ×10−3 dm−6 atm−2 mol2 (3) 1 ,24.62 dm3 atm mol−1 (4) 1 , 4.1 ×10−2 dm−3 atm−1 mol, 1 .65 ×10−3 dm−6 atm−2 mol2 606 dm6 atm2 mol−2 JEE Main 2019 (10 Jan Shift 1) JEE Main Previous Year Paper

Q35.The standard reaction Gibbs energy for a chemical reaction at an absolute temperature T is given by ΔG∘= A −BT where A and B are non-zero constants. Which of the following is true about this reaction? (1) Exothermic if B < 0 (2) Endothermic if A > 0 (3) Endothermic if A < 0 and B > 0 (4) Exothermic if A > 0 and B < 0

Q35.In which one of the following equilibria, Kp ≠Kc? (1) 2HI(g) ⇌H2(g) + I2(g) (2) 2C(s) + O2(g) ⇌2CO(g) (3) 2NO(g) ⇌N2(g) + O2(g) (4) NO2(g) + SO2(g) ⇌NO(g) + SO3(g)