Practice Questions

Q39.The magnetic behaviour of Li2 O, Na2 O2 and KO2 , respectively, are (1) diamagnetic, paramagnetic and diamagnetic (2) paramagnetic, paramagnetic and diamagnetic (3) paramagnetic, diamagnetic and paramagnetic (4) diamagnetic, diamagnetic and paramagnetic

Q40.Ion having highest hydration enthalpy among the given alkaline earth metal ions is: (1) Be2+ (2) Sr2+ (3) Ba2+ (4) Ca2+

Q40.The most stable carbocation for the following is: (1) c (2) d (3) b (4) a

Q40. Mg (NO3)2. XH2 O and Ba (NO3)2. YH2 O, represent formula of the crystalline forms of nitrate salts. Sum of X and Y is.......

Q40.Match List I with List II. List I List II A. Reverberatory furnace I. Pig iron B. Electrolytic cell II. Aluminium C. Blast furnace III. Silicon D. Zone refining furnace IV. Copper JEE Main 2023 (24 Jan Shift 1) JEE Main Previous Year Paper (1) A - IV, B - II, C - I, D - III (2) A - I, B - IV, C - II, D - III (3) A - I, B - III, C - II, D - IV (4) A - III, B - IV, C - I, D - II

Q40.Match List I with List II List I Industry List II Waste Generated (A) Steel plants (I) Gypsum (B) Thermal power plants (II) Fly ash (C) Fertilizer Industries (III) Slag (D) Paper mills (IV) Bio-degradable wastes Choose the correct answer from the options given below : (1) A - III, B - II, C - I, D - IV (2) A - III, B - IV, C - I, D - II (3) A - II, B - III, C - IV, D - I (4) A - IV, B - I, C - II, D - III

Q40.In the extraction of copper, its sulphide ore is heated in a reverberatory furnace after mixing with silica to: (1) separate CuO as CuSiO3 (2) remove calcium as CaSiO3 (3) decrease the temperature needed for roasting of (4) remove FeO as FeSiO3 Cu2S

Q40.In Carius tube, an organic compound ' X ' is treated with sodium peroxide to form a mineral acid ' Y '. The solution of BaCl2 is added to ' Y ' to form a precipitate ' Z '. ' Z ' is used for the quantitative estimation of an JEE Main 2023 (10 Apr Shift 2) JEE Main Previous Year Paper extra element. ' X ' could be (1) Cytosine (2) A nucleotide (3) Methionine (4) Chloroxylenol

Q40.The element playing significant role in neuromuscular function and interneuronal transmission is : (1) Be (2) Mg (3) Ca (4) Li

Q40.When a hydrocarbon A undergoes combustion in the presence of air, it requires 9. 5 equivalents of oxygen and produces 3 equivalents of water. What is the molecular formula of A ? JEE Main 2023 (29 Jan Shift 2) JEE Main Previous Year Paper (1) C8H6 (2) C9H9 (3) C6H6 (4) C9H6

Q40.Match List I with List II LIST I – Enzymatic reaction LIST II - Enzyme A Sucrose→ Glucose and Fructose I Zymase B Glucose → ethyl alcohol and CO2 II Pepsin C Starch → Maltose III Invertase D Proteins → Amino acids IV Diastase Choose the correct answer from the options given below. (1) A - I, B - II, C - IV, D - III (2) A - III, B - I, C - IV, D - II (3) A - III, B - I, C - II, D - IV (4) A - I, B - IV, C - III, D - II

Q40.Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R Assertion A :- Carbon forms two important oxides CO and CO2 . CO is neutral whereas CO2 is acidic in nature. Reason R : CO2 can combine with water in a limited way to form carbonic acid, while CO is sparingly soluble in water. 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.

Q40.Identify X, Y and Z in the following reaction. (Equation not balanced) H2O Cl ∙O + NO2 →X ⟶Y + Z ¯ ¯ ¯ (1) X = ClONO2, Y = HOCl, Z = NO2 (2) X = ClNO2, Y = HCl, Z = HNO3 (3) X = ClONO2, Y = HOCl, Z = HNO3 (4) X = ClNO3, Y = Cl2, Z = NO2

Q40.In the given reaction cycle X, Y and Z respectively are (1) X −CaCO3, Y −NaCl, Z −KCl (2) X −CaCO3, Y −NaCl, Z −HCl (3) X −CaO, Y −NaCl + CO2, Z −NaCl (4) X −CaO, Y −NaCl + CO2, Z −KCl

Q40.The correct order of hydration enthalpies is (A) K+ (B) Rb+ (C) Mg2+ JEE Main 2023 (29 Jan Shift 1) JEE Main Previous Year Paper (D) Cs+ (E) Ca2+ Choose the correct answer from the options given below: (1) C > A > E > B > D (2) E > C > A > B > D (3) C > E > A > D > B (4) C > E > A > B > D

Q40. The correct sequence of reagents for the preparation of Q and R is: (1) (i) Cr2 O3, 770 K, 20 atm ; (ii) (2) (i) CrO2 Cl2, H3O+ ; (ii) CrO2 Cl2, H3O+ ; (iii) NaOH ; (iv) H3O+ Cr2 O3, 770 K, 20 atm; (iii) NaOH; (iv) H3O+ (3) (i) KMnO4, OH− ; (ii) Mo2 O3, Δ; (iii) NaOH; (4) (i) Mo2 O3, Δ; (ii) CrO2 Cl2, H3O+ ; (iii) (iv) H3O+ NaOH; (iv) H3O+

Q41.The density of alkali metals is in the order (1) K < Cs < Na < Rb (2) Na < Rb < K < Cs (3) Na < K < Cs < Rb (4) K < Na < Rb < Cs

Q41.The correct order of pKa values for the following compounds is: (1) c > a > d > b (2) b > d > a > c (3) b > a > d > c (4) a > b > c > d

Q41.An ammoniacal metal salt solution gives a brilliant red precipitate on addition of dimethylglyoxime. The metal ion is : (1) 𝐶𝑢2 + (2) 𝑁𝑖2 + (3) 𝐹𝑒2 + (4) Co2 +

Q41.During the qualitative analysis of SO32 - using dilute H2SO4, SO2 gas is evolved which turns K2Cr2O7 solution (acidified with dilute H2SO4): (1) Black (2) Red (3) Green (4) Blue

Q41.Structures of BeCl2 in solid state, vapour phase and at very high temperature respectively are: (1) Monomeric, Dimeric, Polymeric (2) Dimeric, Polymeric, Monomeric (3) Polymeric, Monomeric, Dimeric (4) Polymeric, Dimeric, Monomeric

Q41.Given below are two statements: Statement I: Sulphanilic acid gives esterification test for carboxyl group. Statement II: Sulphanilic acid gives red colour in Lassigne’s test for extra element detection. In the light of the above statements, choose the most appropriate answer from the options given below: JEE Main 2023 (01 Feb Shift 2) JEE Main Previous Year Paper (1) Statement I is correct but Statement II is (2) Both Statement I and Statement II are incorrect incorrect. (3) Both Statement I and Statement II are correct (4) Statement I is incorrect but Statement II is correct.

Q41.In the extraction process of copper, the product obtained after carrying out the reactions (i) 2Cu2 S + 3O2 ⟶2Cu2O + 2SO2 (ii) 2Cu2O + Cu2 S ⟶6Cu + SO2 is called (1) Blister copper (2) Reduced copper (3) Copper scrap (4) Copper matte

Q41.Some reactions of NO2 relevant to photochemical smog formation are Identify A, B, X and Y (1) X = [O], Y = NO, A = O2, B = O3 (2) X = N2O, Y = [O], A = O3, B = NO (3) X = 12 O2, Y = NO2, A = O3, B = O2 (4) X = NO, Y = [O], A = O2, B = N2O3 JEE Main 2023 (25 Jan Shift 1) JEE Main Previous Year Paper

Q41.Which of the following can reduce decomposition of H2O2 on exposure to light (1) Urea (2) Alkali (3) Glass containers (4) Dust