Practice Questions

Q70.Which of the following linear combination of atomic orbitals will lead to formation of molecular orbitals in homonuclear diatomic molecules [internuclear axis in z -direction] ? A. 2pz and 2px B. 2 s and 2px C. 3 dxy 2025 (24 Jan Shift 1) JEE Main Previous Year Paper and 3 dx2−y2 D. 2 s and 2pz E. 2pz and 3dx2 −y2 Choose the correct answer from the options given below: (1) A and B Only (2) D Only (3) E Only (4) C and D Only

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

Q71.The molar mass of the water insoluble product formed from the fusion of chromite ore (FeCr2O4) with Na2CO3 in presence of O2 is _______ gmol−1 .

Q31.Which of the following cannot function as an oxidising agent? (1) N3 - (2) SO42 - (3) BrO3- (4) MnO4-

Q31.Combustion of glucose (C6H12O6) produces CO2 and water. The amount of oxygen (in g) required for the complete combustion of 900 g of glucose is : [Molar mass of glucose in gmol−1 = 180 ] (1) 480 (2) 800 (3) 960 (4) 32

Q31.The density of ' x ' M solution (' X ' molar) of NaOH is 1.12 g mL−1 , while in molality, the concentration of the solution is 3 m(3molal). Then x is (Given : Molar mass of NaOH is 40 g/mol ) (1) 3.5 (2) 3.8 (3) 2.8 (4) 3.0

Q31.A sample of CaCO3 and MgCO3 weighed 2 .21 g is ignited to constant weight of 1 .152 g. The composition of the mixture is: (Given molar mass in g mol−1, CaCO3: 100, MgCO3: 84) (1) 1 .187 𝑔 𝐶𝑎𝐶𝑂3 + 1 .023 𝑔 𝑀𝑔𝐶𝑂3 (2) 1 .023 𝑔 𝐶𝑎𝐶𝑂3 + 1 .023 𝑔 𝑀𝑔𝐶𝑂3 (3) 1 .187 𝑔 𝐶𝑎𝐶𝑂3 + 1 .187 𝑔 𝑀𝑔𝐶𝑂3 (4) 1 .023 𝑔 𝐶𝑎𝐶𝑂3 + 1 .187 𝑔 𝑀𝑔𝐶𝑂3

Q31.Number of elements from the following that CANNOT form compounds with valencies which match with their respective group valencies is ______. B, C, N, S, O, F, P, Al, Si (1) 7 (2) 3 (3) 5 (4) 6

Q31.An organic compound has 42.1% carbon, 6.4% hydrogen and remainder is oxygen. If its molecular weight is 342, then its molecular formula is : (1) C11H18O12 (2) C12H20O12 (3) C12H22O11 (4) C14H20O10

Q31.The correct set of four quantum numbers for the valence electron of rubidium atom (Z = 37) is: (1) 5, 0, 0, + 12 (2) 5, 0, 1, + 12 (3) 5, 1, 0, + 12 (4) 5, 1, 1, + 12

Q31.The number of moles of methane required to produce 11 gCO2( g) after complete combustion is : (Given molar mass of methane in gmol−1 : 16) (1) 0.35 (2) 0.5 (3) 0.75 (4) 0.25

Q31.Molality ( m ) of 3M aqueous solution of NaCl is : (Given : Density of solution = 1.25 g mL−1 , Molar mass in gmol−1 : Na −23, Cl −35.5) JEE Main 2024 (06 Apr Shift 2) JEE Main Previous Year Paper (1) 1.9 m (2) 3.85 m (3) 2.79 m (4) 2.90 m

Q31.The candela is the luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency ' A ' ×1012 hertz and that has a radiant intensity in that direction of ′ 1B′ watt per steradian. 'A' and 'B' are respectively (1) 540 and 683 (2) 450 and 683 (3) 450 and 1 (4) 540 and 1 683 683

Q31.The correct sequence of electron gain enthalpy of the elements listed below is A. Ar B. Br C. F D. S Choose the most appropriate from the options given below: (1) C > B > D > A (2) A > D > B > C (3) A > D > C > B (4) D > C > B > A

Q31.The electronic configuration for Neodymium is: [Atomic Number for Neodymium 60] JEE Main 2024 (27 Jan Shift 1) JEE Main Previous Year Paper (1) [Xe] 4f 4 6s2 (2) [Xe] 5f 47s2 (3) [Xe] 4f 6 6s2 (4) [Xe] 4f 15d16s2

Q31.The number of radial node/s for 3p orbital is: (1) 1 (2) 4 (3) 2 (4) 3

Q31.Identify the correct statements about p-block elements and their compounds. (A) Non metals have higher electronegativity than metals. (B) Non metals have lower ionisation enthalpy than metals. (C) Compounds formed between highly reactive nonmetals and highly reactive metals are generally ionic. (D) The non-metal oxides are generally basic in nature. (E) The metal oxides are generally acidic or neutral in nature. Choose the correct answer from the options given below : (1) (B) and (D) only (2) (A) and (C) only (3) (D) and (E) only (4) (B) and (E) only

Q31.Match List I with List II Choose the correct answer from the options given below :- (1) A-II, B-III, C-I, D-IV (2) A-I, B-III, C-II, D-IV (3) A-II, B-IV, C-III, D-I (4) A-I, B-II, C-III, D-IV

Q31.Compare the energies of following sets of quantum numbers for multielectron system. (A) n = 4, 1 = 1 (B) n = 4, l = 2 (C) n = 3, 1 = 1 (D) n = 3, 1 = 2 (E) n = 4, 1 = 0 Choose the correct answer from the options given below : (1) (B) > (A) > (C) > (E) > (D) (2) (E) < ( C ) < (D) < ( A ) < ( B ) (3) (E) > ( C ) > ( A ) > ( D ) > (B) (4) (C) < (E) < (D) < (A) < (B)

Q32.The shape of carbocation is : (1) diagonal pyramidal (2) trigonal planar (3) tetrahedral (4) diagonal

Q32.In case of isoelectronic species the size of F–, Ne and Na+ is affected by: (1) Principal quantum number n (2) None of the factors because their size is the same (3) Electron-electron interaction in the outer orbitals (4) Nuclear charge z

Q32.The molecular formula of second homologue in the homologous series of mono carboxylic acids is _________. (1) C3H6O2 (2) C2H4O2 (3) CH2O (4) C2H2O2

Q32.The element having the highest first ionization enthalpy is (1) Si (2) Al (3) N (4) C

Q32.The electronic configuration of Einsteinium is : (Given atomic number of Einsteinium = 99) (1) [Rn]5f 106 d∘7 s2 (2) [Rn]5f 136 d∘7 s2 (3) [Rn]5f 116 d∘7 s2 (4) [Rn]5f 126 d∘7 s2

Q32.The four quantum numbers for the electron in the outer most orbital of potassium (atomic no. 19) are (1) n = 4, l = 2, m = −1, s = + 1 (2) n = 4, l = 0, m = 0, s = + 1 2 2 1 1 (3) n = 3, l = 0, m = −1, s = + (4) n = 2, l = 0, m = 0, s = + 2 2