Practice Questions

Q39.Boric acid in solid, whereas BF3 is gas at room temperature because of (1) Strong ionic bond in Boric acid (2) Strong van der Waal's interaction in Boric acid (3) Strong hydrogen bond in Boric acid (4) Strong covalent bond in BF3

Q40.Which of the following are the Green house gases? A. Water vapour B.Ozone C.I2 D.Molecular hydrogen Choose the most appropriate answer from the options given below : (1) A and D only (2) B and C only (3) A and B only (4) C and D only

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.Given below are two statements: Statement I: In redox titration, the indicators used are sensitive to change in pH of the solution. Statement II: In acid-base titration, the indicators used are sensitive to change in oxidation potential. In the light of the above statements, choose the most appropriate answer from the options given below (1) Statement I is correct but Statement II is (2) Both Statement I and Statement II are incorrect incorrect (3) Statement I is incorrect but Statement II is (4) Both Statement I and Statement II are correct correct

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.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. 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.The possibility of photochemical smog formation will be minimum at (1) Srinagar, Jammu and Kashmir in January (2) Kolkata in October (3) Mumbai in May (4) New-Delhi in August (Summer)

Q40. KMnO4 is titrated with ferrous ammonium sulphate hexahydrate in presence of dilute H2 SO4. Number of water molecules produced for 2 molecules of KMnO4 is _______ Q41. 20 mL of calcium hydroxide was consumed when it was reacted with 10 mL of unknown solution of H2 SO4. Also 20 mL standard solution of 0. 5 M HCl containing 2 drops of phenolphthalein was titrated with calcium hydroxide, the mixture showed pink colour when burette displayed the value of 35. 5 mL whereas the burette showed 25. 5 mL initially. The concentration of H2 SO4 is _______M. (Nearest integer)

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

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+

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.Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R. Assertion A : Beryllium has less negative value of reduction potential compared to the other alkaline earth metals Reason R : Beryllium has large hydration energy due to small size of Be2+ but relatively large value of atomisation enthalpy. In the light of the above statements, choose the most appropriate answer from the options given below. (1) A is correct but R is not correct (2) Both A and R are correct and R is the correct explanation of A (3) A is not correct but R is correct (4) Both A and R are correct and R is NOT the correct explanation of A

Q40.Given below are two statements : Statement I : Lithium and Magnesium do not form superoxide Statement II : The ionic radius of Li+ is larger than ionic radius of Mg2+ In the light of the above statements, choose the most appropriate answer from the questions given below : In the light of the above statements, choose the most appropriate answer from the questions given below : (1) Statement I is incorrect but Statement II is (2) Statement I is correct but Statement II is correct incorrect (3) Both statement I and Statement II are incorrect (4) Both Statement I and Statement II are correct

Q40.Given below are two statements : Statement-I : If BOD is 4 ppm and dissolved oxygen is 8 ppm , then it is a good quality water. Statement-II : If the concentration of zinc and nitrate salts are 5 ppm each, then it can be a good quality water. In the light of the above statements, choose the most appropriate answer from the options given below : (1) Statement I is correct but Statement II is (2) Statement I is incorrect but Statement II is incorrect correct (3) Both the statements I and II are incorrect (4) Both the statements I and II are correct

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

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.Given below are two statements: Statement I: Chlorine can easily combine with oxygen to from oxides: and the product has a tendency to explode. JEE Main 2023 (01 Feb Shift 1) JEE Main Previous Year Paper Statement II: Chemical reactivity of an element can be determined by its reaction with oxygen and halogens. In the light of the above statements, choose the correct answer from the options given below (1) Both the statements I and II are true (2) Statement I is true but Statement II is false (3) Statement I is false but Statement II is true (4) Both the Statements I and II are false

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

Q40.The correct order of bond enthalpy ( kJ mol–1 ) is: (1) Si −Si > C −C > Sn −Sn > Ge −Ge (2) Si −Si > C −C > Ge −Ge > Sn −Sn (3) C −C > Si −Si > Sn −Sn > Ge −Ge (4) C −C > Si −Si > Ge −Ge > Sn −Sn