Practice Questions

Q60.Oxidation state of Fe(Iron) in complex formed in Brown ring test.

Q60.The compound formed by the reaction of ethanal with semicarbazide contains _______ number of nitrogen atoms. ¯

Q60.The number of tripeptides formed by three different amino acids using each amino acid once is _______.

Q61.The sum of all possible values of θ ∈[−π, 2π], for which 1−2i1+i coscosθθ is purely imaginary, is equal (1) 3π (2) 2π (3) 5π (4) 4π

Q61.The area (in sq. units) of the region S = {z ∈C : |z −1| ≤2; (z + ¯z) + i(z −¯z) ≤2, Im(z) ≥0} is (1) 7π (2) 7π 3 4 (3) 17π (4) 3π 8 2

Q62.Let Sa denote the sum of first n terms an arithmetic progression. If S20 = 790 and S10 = 145, then S15−S5 is : JEE Main 2024 (30 Jan Shift 1) JEE Main Previous Year Paper (1) 395 (2) 390 (3) 405 (4) 410

Q31.Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R Assertion A: Hydrogen is an environment friendly fuel. Reason R: Atomic number of hydrogen is 1 and it is a very light element. In the light of the above statements, choose the correct answer from the options given below (1) A is true but R is false (2) Both A and R are true but R is NOT the correct explanation of A (3) A is false but R is true (4) Both A and R are true and R is the correct explanation of A

Q31.Which of the following have same number of significant figures? (A) 0. 00253 (B) 1. 0003 (C) 15. 0 (D) 163 Choose the correct answer from the options given below (1) A, B and C only (2) C and D only (3) B and C only (4) A, C and D only

Q31.The number of molecules and moles in 2 . 8375 litres of O2 at STP are respectively (1) 7 . 527 × 1023 and 0 . 125 mol (2) 7 . 527 × 1022 and 0 . 250 mol (3) 1 . 505 × 1023 and 0 . 250 mol (4) 7 . 527 × 1022 and 0 . 125 mol

Q31.Match List - I with List - II LIST-II LIST-I (Block of periodic (Atomic number) table) (A) 37 I. p-block (B) 78 II. d-block JEE Main 2023 (30 Jan Shift 1) JEE Main Previous Year Paper (C) 52 III. f-block (D) 65 IV. s-block Choose the correct answer from the options given below: (1) A - II, B - IV, C - I, D - III (2) A - I, B - III, C - IV, D - II (3) A - IV, B - III, C - II, D - I (4) A - IV, B - II, C - I, D - III

Q31.It is observed that characteristic X-ray spectra of elements show regularity. When frequency to the power 'n' i.e. vn of X-rays emitted is plotted against atomic number Z, the following graph is obtained. The value of 'n' is JEE Main 2023 (24 Jan Shift 1) JEE Main Previous Year Paper (1) 1 (2) 2 1 (3) (4) 3 2

Q31.A solution is prepared by adding 2 g of ′′X′′ to 1 mole of water. Mass percent of ′′X′′in solution is (1) 5% (2) 20% (3) 2% (4) 10% JEE Main 2023 (11 Apr Shift 2) JEE Main Previous Year Paper

Q31.Assume that the radius of the first Bohr orbit of hydrogen atom is 0. 6Å . The radius of the third Bohr orbit of He+ is _____ picometer. (Nearest Integer)

Q32.The total number of lone pairs of electrons on oxygen atoms of ozone is

Q32.Maximum number of electrons that can be accommodated in shell with n = 4 are: (1) 16 (2) 32 (3) 50 (4) 72

Q32.Which one of the following sets of ions represents a collection of isoelectronic species? (Given : Atomic Number : F : 9, Cl : 17, Na = 11 Mg = 12, Al = 13, K = 19, Ca = 20, Sc = 21) (1) (Li+, Na+, Mg2+, Ca2+ (2) (Ba2+, Sr2+, K+, Ca2+ (3) (N3−, O2−, F−, S2− (4) (K+, Cl−, Ca2+, Sc3+

Q32.The number of given orbitals which have electron density along the axis is px, py, pz, dxy, dyz, dxz, d2z, dx2−y2

Q32.The energy of an electron in the first Bohr orbit of hydrogen atom is −2. 18 × 10−18 J Its energy in the third Bohr orbit is _______. (1) 9 1 th of the value (2) 271 of this value (3) Three times of this value (4) One third of this value

Q32.Match List I with List II (A) Slaked lime (I) NaOH (B) Dead burnt plaster (II) Ca ( OH ) 2 (C) Caustic soda (III) Na2CO3 · 10H2O (D) Washing soda (IV) CaSO4 Choose the correct answer form the options given below: (1) (A) - I, (B) - IV, (C) - II, (D) - III (2) (A) - III, (B) - IV, (C) - II, (D) - I (3) (A) - II, (B) - IV, (C) - I, (D) - III (4) (A) - III, (B) - II, (C) -IV, (D) -I

Q32.Which of the following options are correct for the reaction? - 2 - 2Au ( CN ) 2 (aq) + Zn(s) →2Au(s) + Zn ( CN ) 4 (aq) A. Redox reaction B. Displacement reaction C. Decomposition reaction D. Combination reaction Choose the correct answer from the options given below: (1) A only (2) A and D only (3) A and B only (4) C and D only

Q32.The bond dissociation energy is highest for (1) Cl2 (2) I2 (3) Br2 (4) F2

Q33.Group- 13 elements react with O2 in amorphous form to form oxides of type M2O3 ( M = element). Which among the following is the most basic oxide? (1) Al2 O3 (2) B2O3 (3) Tl2 O3 (4) Ga2 O3

Q33.Statement I:- Dipole moment is a vector quantity and by convention it is depicted by a small arrow with tail on the negative centre and head pointing towards the positive centre. Statement II:- The crossed arrow of the dipole moment symbolizes the direction of the shift of charges in the molecules. In the light of the above statements, choose the most appropriate answer from the options given below:- (1) Both Statement I and Statement II are correct. (2) Statement I is incorrect but Statement II is correct. (3) Both Statement I and Statement II are incorrect. (4) Statement I is correct but Statement II is incorrect. Q34. 28. 0 L of CO2 is produced on complete combustion of 16. 8 L gaseous mixture of ethene and methane at 25°C and 1 atm. Heat evolved during the combustion process is kJ Given : ΔHC(CH4) = −900 kJ mol−1 ΔHC(C2H4) = −1400 kJ mol−1 .

Q33.Arrange the following orbitals in decreasing order of energy. A. n = 3, l = 0, m = 0 B. n = 4, l = 0, m = 0 C. n = 3, l = 1, m = 0 D. n = 3, l = 2, m = 1 The correct option for the order is: (1) D > B > C > A (2) B > D > C > A (3) A > C > B > D (4) D > B > A > C

Q34.During water-gas shift reaction (1) Carbon monoxide is oxidized to carbon dioxide. (2) Water is evaporated in presence of catalyst. (3) Carbon is oxidized to carbon monoxide. (4) Carbon dioxide is reduced to carbon monoxide.