Practice Questions

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

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

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.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, 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.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 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

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. 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.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)

Q41.Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R. Assertion A : The diameter of colloidal particles in solution should not be much smaller than wavelength of light to show Tyndall effect. Reason R : The light scatters in all directions when the size of particles is large enough. In the light of the above statements, choose the correct answer from the options given below : JEE Main 2023 (13 Apr Shift 2) JEE Main Previous Year Paper (1) Both A and R are correct but R is NOT the (2) A is true but R is false correct explanation of A (3) A is false but R is true (4) Both A and R are correct and R is the correct explanation of A

Q41.During the borax bead test with CuSO4 , a blue green colour of the bead was observed in oxidising flame due to the formation of (1) Cu3 B2 (2) Cu (3) Cu (BO2)2 (4) CuO

Q41.What is the purpose of adding gypsum to cement? (1) To facilitate the hydration of cement (2) To slow down the process of setting (3) To give a hard mass (4) To speed up the process of setting

Q41.When Cu2 + ion is treated with KI, a white precipitate, X appears in solution. The solution is titrated with sodium thiosulphate, the compound Y is formed. X and Y respectively are (1) X = Cu2I2, Y = Na2S4O5 (2) X = Cu2I2, Y = Na2S4O6 (3) X = CuI2, Y = Na2S4O3 (4) X = CuI2, Y = Na2S4O6

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.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.A solution of FeCl3 when treated with K4Fe ( CN ) gives a prussian blue precipitate due to the formation of 6 (1) KFe2 ( CN ) (2) FeFe ( CN ) 6 6 (3) Fe3Fe ( CN ) (4) Fe4Fe ( CN ) 62 63

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

Q41.Compound from the following that will not produce precipitate on reaction with AgNO3 is JEE Main 2023 (11 Apr Shift 2) JEE Main Previous Year Paper (1) (2) (3) (4)

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.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