Practice Questions

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.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.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.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

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

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

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.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.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.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

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

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

Q34.The alkaline earth metal sulphate(s) which are readily soluble in water is/are: (A) BeSO4 (B) MgSO4 (C) CaSO4 (D) SrSO4 (E) BaSO4 Choose the correct answer from the options given below: (1) A only (2) B only (3) A and B (4) B and C

Q34.The correct order of metallic character is (1) K > Be > Ca (2) Be > Ca > K (3) Ca > K > Be (4) K > Ca > Be

Q34.Resonance in carbonate ion CO32 - is Which of the following is true? (1) It is possible to identify each structure (2) All these structures are in dynamic equilibrium individually by some physical or chemical with each other. method. (3) Each structure exists for equal amount of time. (4) CO32 - has a single structure i.e., resonance hybrid of the above three structures.

Q34.Which of the following relations are correct? (A) ΔU = q + pΔV (B) ΔG = ΔH −TΔS (C) ΔS = qrevT (D) ΔH = ΔU −ΔnRT Choose the most appropriate answer from the options given below : (1) C and D only (2) B and C only (3) A and B only (4) B and D only

Q34.Match Column I with Column II Column I Column II A Soda ash I CaSO4 B Chlorophyll II CaOH2 C Used in Whitewashing III Na2CO3 D Dentistry, ornamental work IV Mg2 + ions (1) A – III, B – IV, C – I, D – II (2) A – II, B – I, C – III, D – IV (3) A – III, B – I, C – II, D – IV (4) A – II, B – III, C – IV, D – I

Q35.Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R. Assertion A : Isotopes of hydrogen have almost same chemical properties, but difference in their rates of reactions. Reason R: Isotopes of hydrogen have different enthalpy of bond dissociation. In the light of the above statements, choose the most appropriate answer from the options given below: (1) Both A and R are correct but R is NOT the (2) Both A and R are correct and R is the correct correct explanation of A explanation of A (3) A is not correct but R is correct (4) A is correct but R is not correct

Q35.The setting time of Cement is increased by adding (1) Clay (2) Silica (3) Gypsum (4) Limestone

Q35.Lithium aluminium hydride can be prepared from the reaction of (1) LiCl and Al2H6 (2) LiH and Al2Cl6 (3) LiCl, Al and H2 (4) LiH and AlOH3

Q36.Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A) : An aqueous solution of KOH when for volumetric analysis, its concentration should be checked before the use. Reason (R) : On aging, KOH solution absorbs atmospheric CO2 . In the light of the above statements, choose the correct answer from the options given below. (1) (A) is not correct but (R) is correct (2) Both (A) and (R) are correct but (R) is not the correct explanation of (A) (3) Both (A) and (R) are correct and (R) is the (4) (A) is correct but (R) is not correct correct explanation of (A)

Q36.How can photochemical smog be controlled? (1) By using tall chimneys (2) By complete combustion of fuel (3) By using catalytic converters in (4) By using catalyst the automobiles/industry

Q36.For a good quality cement, the ratio of silica to alumina is found to be (1) 1. 5 (2) 4. 5 (3) 2 (4) 3

Q36.Match List I with List II List I List II A. Cobalt catalyst I. (H2 + Cl2) production B. Syngas II. Water gas production C. Nickel catalyst III. Coal gasification D. Brine solution IV. Methanol production Choose the correct answer from the options given below:- JEE Main 2023 (25 Jan Shift 2) JEE Main Previous Year Paper (1) A-IV, B-I, C-II, D-III (2) A-IV, B-III, C-I, D-II (3) A-II, B-III, C-IV, D-I (4) A-IV, B-III, C-II, D-I

Q37.Which of the following is true about freons? (1) These are chlorofluorocarbon compounds (2) These are chemicals causing skin cancer (3) These are radicals of chlorine and chlorine (4) All radicals are called freons monoxide