Practice Questions

Q62.The type of oxide formed by the element among Li, Na, Be, Mg, B and Al that has the least atomic radius is : (1) A2O (2) A2O3 (3) AO2 (4) AO

Q62.In the given structure, number of sp and sp2 hybridized carbon atoms present respectively are : (1) 4 and 5 (2) 3 and 5 (3) 3 and 6 (4) 4 and 6 2025 (24 Jan Shift 2) JEE Main Previous Year Paper

Q63.Given below are two statements I and II. Statement I: Dumas method is used for estimation of "Nitrogen" in an organic compound. Statement II: Dumas method involves the formation of ammonium sulphate by heating the organic compound with conc H2SO4 . In the light of the above statements, choose the correct answer from the options given below (1) Statement I is true but Statement II is false (2) Both Statement I and Statement II are false (3) Statement I is false but Statement II is true (4) Both Statement I and Statement II are true

Q63.Total number of sigma ( σ ) and pi(π) bonds respectively present in hex-1-en-4-yne are : (1) 3 and 13 (2) 11 and 3 (3) 13 and 3 (4) 14 and 3

Q63.Given below are two statements : Statement (I) : The boiling points of alcohols and phenols increase with increase in the number of C-atoms. Statement (II) : The boiling points of alcohols and phenols are higher in comparison to other class of compounds such as ethers, haloalkanes. In the light of the above statements, choose the correct answer from the options given below : (1) Both Statement I and Statement II are false (2) Both Statement I and Statement II are true (3) Statement I is false but Statement II is true (4) Statement I is true but Statement II is false

Q65.Given below are two statements : Statement (I): According to the Law of Octaves, the elements were arranged in the increasing order of their atomic number. Statement (II): Meyer observed a periodically repeated pattern upon plotting physical properties of certain elements against their respective atomic numbers. In the light of the above statements, choose the correct answer from the options given below : (1) Both Statement (I) and Statement (II) are false. (2) Both Statement (I) and Statement (II) are true. (3) Statement (I) is false but Statement (II) is true. (4) Statement (I) is true but Statement (II) is false. 2025 (28 Jan Shift 2) JEE Main Previous Year Paper

Q66.Match List - I with List - II. List −I List −II (A) Bronze (I) Cu, Ni (B) Brass (II) Fe, Cr, Ni, C (C) UKsilvercoin (III) Cu, Zn (D) Stainlesssteel (IV ) Cu, Sn Choose the correct answer from the options given below : (1) (A)-(IV), (B)-(II), (C)-(III), (D)-(I) (2) (A)-(IV), (B)-(III), (C)-(I), (D)-(II) (3) (A)-(III), (B)-(IV), (C)-(II), (D)-(I) (4) (A)-(III), (B)-(I), (C)-(IV), (D)-(II)

Q66.What is the freezing point depression constant of a solvent, 50 g of which contain 1 g non volatile solute (molar mass 256 g mol−1 ) and the decrease in freezing point is 0.40 K ? (1) 3.72 K kg mol−1 (2) 1.86 K kg mol−1 (3) 4.43 K kg mol−1 (4) 5.12 K kg mol−1 2025 (28 Jan Shift 1) JEE Main Previous Year Paper

Q67.The correct option with order of melting points of the pairs (Mn, Fe), (Tc, Ru) and (Re, Os) is : (1) Fe < Mn, Ru < Tc and Re < Os (2) Mn < Fe, Tc < Ru and Os < Re (3) Mn < Fe, Tc < Ru and Re < Os (4) Fe < Mn, Ru < Tc and Os < Re 2025 (29 Jan Shift 1) JEE Main Previous Year Paper

Q67. An ideal gas undergoes a cyclic transformation starting from the point A and coming back to the same point by tracing the path A →B →C →D →A as shown in the three cases above. Choose the correct option regarding ΔU : (1) ΔU( Case-I ) = ΔU( Case-II ) = ΔU( Case-III (2) ΔU( Case-I ) > ΔU( Case-III ) > ΔU( Case-II ) ) (3) ΔU( Case-III ) > ΔU( Case-II ) > ΔU( Case-I (4) ΔU( Case-I ) > ΔU( Case-II ) > ΔU( Case-III ) )

Q67.Match the LIST-I with LIST-II Choose the correct answer from the options given below: (1) A-II, B-I, C-III, D-IV (2) A-II, B-III, C-I, D-IV (3) A-IV, B-I, C-III, D-II (4) A-IV, B-III, C-I, D-II

Q68.pH of water is 7 at 25∘C. If water is heated to 80∘C., it's pH will : (1) Decrease (2) H+ concentration increases, OH− concentration decreases (3) Remains the same (4) Increase 2025 (23 Jan Shift 2) JEE Main Previous Year Paper

Q70.If C (diamond ) →C (graphite ) + XkJmol−1 C( diamond ) + O2( g) →CO2( g) + YkJmol−1 C (graphite) +O2( g) →CO2( g) + ZkJmol−1 at constant temperature. Then (1) X=-Y+Z (2) -X=Y+Z (3) X=Y+Z (4) X=Y-Z

Q70.The correct stability order of the following species/molecules is: (1) q > r > p (2) r > q > p (3) q > p > r (4) p > q > r Q71. 1 The standard enthalpy and standard entropy of decomposition of N2O4 to NO2 are 55.0 kJ mol−1 and 175.0 J/K/mol respectively. The standard free energy change for this reaction at 25∘C in J mol−1 is ______ (Nearest integer)

Q71.In the sulphur estimation, 0.20 g of a pure organic compound gave 0.40 g of barium sulphate. The percentage of sulphur in the compound is ______ ×10−1% . (Molar mass : O = 16, S = 32, Ba = 137 in gmol−1 ) 2025 (29 Jan Shift 2) JEE Main Previous Year Paper

Q73.Consider the following cases of standard enthalpy of reaction (ΔH∘r in kJmol−1) 7 C2H6( g) + O2( g) →2CO2( g) + 3H2O(l)ΔH∘1 = −1550 2 C (graphite) + O2( g) →CO2( g) ΔH∘2 = −393.5 The magnitude of ΔH∘fC2H6( g) is _______ 1 H2( g) + O2( g) →H2O(l) ΔH∘3 = −286 2 kJmol−1 (Nearest integer).

Q74.Quantitative analysis of an organic compound (X) shows following \% composition. C : 14.5% Cl : 64.46\% H: 1.8 \% (Empirical formula mass of the compound (X) is __________ ×10−1 (Given molar mass in gmol−1 of C : 12, H : 1, O : 16, Cl : 35.5 )

Q75.The complex of Ni2+ ion and dimethyl glyoxime contains ________ number of Hydrogen (H) atoms. 2025 (22 Jan Shift 2) JEE Main Previous Year Paper

Q75.Total number of non bonded electrons present in NO2− ion based on Lewis theory is 2025 (29 Jan Shift 2) JEE Main Previous Year Paper

Q1. The equation of state of a real gas is given by 𝑃+ 𝑎 (𝑉- 𝑏) = 𝑅𝑇, where 𝑃, 𝑉 and 𝑇 are pressure, volume 𝑉2 a and temperature respectively and 𝑅 is the universal gas constant. The dimensions of is similar to that of : b2 (1) 𝑃𝑉 (2) 𝑃 (3) 𝑅𝑇 (4) 𝑅

Q1. Match List-I with List-II. List-I List-II A. Coefficient of viscosity I. [ML2 T−2] B. Surface Tension II. [ML2 T−1] C. Angular momentum III. [ML−1 T−1] D. Rotational kinetic energy IV. [ML0 T−2] (1) A-II, B-I, C-IV, D-III (2) A-I, B-II, C-III, D-IV (3) A-III, B-IV, C-II, D-I (4) A-IV, B-III, C-II, D-I

Q1. If the percentage errors in measuring the length and the diameter of a wire are 0 . 1% each. The percentage error in measuring its resistance will be: (1) 0 . 2% (2) 0 . 3% (3) 0 . 1% (4) 0 . 144% Q2. 1 𝑏2 A force is represented by 𝐹= 𝑎𝑥2 + 𝑏𝑡 2, where 𝑥= distance and 𝑡= time. The dimensions of are : 𝑎 (1) [𝑀𝐿3 𝑇 – 3 ] (2) [𝑀𝐿𝑇– 2] (3) [𝑀𝐿– 1 𝑇– 1] (4) [𝑀𝐿2 𝑇– 3]

Q1. A physical quantity Q is found to depend on quantities a, b, c by the relation Q = a4b3 . The percentage error in c2 a, b and c are 3%, 4% and 5% respectively. Then, the percentage error in Q is: (1) 66% (2) 43% (3) 34% (4) 14%

Q1. If two vectors →𝐴 and →𝐵 having equal magnitude 𝑅 are inclined at an angle 𝜃, then 𝜃 2𝑅sin (1) →𝐴− →𝐵= √2𝑅sin 𝜃2 (2) →𝐴+ →𝐵= 2 → → 𝜃 → → 𝜃 (3) 𝐴+ 𝐵= 2𝑅cos (4) 𝐴− 𝐵= 2𝑅cos 2 2

Q1. The resistance R = VI , where V = (200 ± 5) V and I = (20 ± 0. 2) A, the percentage error in the measurement of R is : (1) 3. 5% (2) 7% (3) 3% (4) 5. 5%