Practice Questions

Q24.A loop ABCDEFA of straight edges has six corner points A(0, 0, 0), B(5, 0, 0), C(5, 5, 0), D(0, 5, 0), E(0, 5, 5) and F(0, 0, 5) . The magnetic field in this region is → B = + ABCDEFA (in Wb ) is _____________ (3ˆi 4ˆk)T . The quantity of flux through the loop

Q24.The series combination of two batteries, both of the same emf 10V, but different internal resistance of 20 Ω and 5 Ω, is connected to the parallel combination of two resistors 30 Ω and x Ω. The voltage difference across the battery of internal resistance 20 Ω is zero, the value of x (in Ω) is____ ∘

Q25.A beam of electromagnetic radiation of intensity 6.4 × 10−5W/cm2 is comprised of wavelength, λ = 310nm . It falls normally on a metal (work function φ = 2eV ) of surface area of 1cm2 . If one in 103 photons ejects an election, total number of electrons ejected in 1s is 10x . (hc = 1240eVnm, 1eV = 1.6 × 10−19J), then x is ___________

Q25.In the line spectra of hydrogen atom, difference between the largest and the shortest wavelengths of the Lyman ∘ ∘ series is 305 A . The corresponding difference for the Paschan series in A is:________

Q27.Consider the hypothetical situation where the azimuthal quantum number, 𝓁 , takes values 0, 1, 2, … … . . n + 1. Where n is the principal quantum number. Then, the element with atomic number: (1) 9 is the first alkali metal (2) 13 has a half-filled valence subshell (3) 8 is the first noble gas (4) 6 has a 2p-valence subshell JEE Main 2020 (03 Sep Shift 2) JEE Main Previous Year Paper

Q27.The variation of equilibrium constant with temperature is given below : Temperature EquilibriumConstant T1 = 25°C K1 = 10 T2 = 100°C K2 = 100 JEE Main 2020 (06 Sep Shift 1) JEE Main Previous Year Paper The values of ΔH°, ΔG° at T1 and ΔG° at T2 (in kJ mol−1 ) respectively, are close to [use R = 8. 314 JK−1 mol−1 ] (1) 28. 4, −7. 14 and −5. 71 (2) 0. 64, −7. 14 and −5. 71 (3) 28. 4, −5. 71 and −14. 29 (4) 0. 64, −5. 71 and −14. 29

Q29.Among the compounds A and B with molecular formula C9H18O3, A is having higher boiling point than B. The possible structures of A and B are: JEE Main 2020 (08 Jan Shift 2) JEE Main Previous Year Paper (1) (2) (3) (4)

Q33.An organic compound ' A ' (C9H10O) when treated with conc. HI undergoes cleavage to yield compound ' B ' and ' C'. ' B' gives yellow precipitate with AgNO3 where as ' C ' tautomerizes to ' D '. ' D ' gives positive iodoform test. ' A' could be: (1) (2) (3) (4)

Q35.An unsaturated hydrocarbon X absorbs two hydrogen molecules on catalytic hydrogenation, and also gives following reaction: (i)O3 [Ag (NH3)2]+ −−X → A → B (3-oxo-hexanedicarboxylic acid) X will be: (ii) Zn H2O (1) (2) (3) (4)

Q36.An element crystallises in a face–centred cubic (fcc) unit cell with cell edge a. The distance between the centres of two nearest octahedral voids in the crystal lattice is: (1) a (2) a √2 (3) √2a (4) a2

Q36.Let CNaCl and CBaSO4 , be the conductances (in S) measured for saturated aqueous solutions of NaCl and BaSO4 respectively, at a temperature T. Which of the following is false? (1) lonic mobilities of ions from both salts increase with T. (2) CBaSO4(T2) > CBaSO4(T1) for T2 > T1 (3) CNaCl(T2) > CNaCl(T1) for T2 > T1 (4) CNaCl ≫CBaSO4 at given T

Q39.The correct order of the spin-only magnetic moments of the following complexes is: (I) [Cr(H2O)6]Br2 (II) Na4[Fe(CN)6] (III) Na3[Fe(C2O4)3](Δ0 > P) (IV) (Et4N)2[CoCl4] (1) (III) > (I) > (IV) > (II) (2) (III) > (I) > (II) > (IV) (3) (I) > (IV) > (III) > (II) (4) (II) ≈(I) > (IV) > (III)

Q40.Complex X Of composition Cr(H2O)6Cln Has a spin only magnetic moment of 3.83 B. M. It reacts with AgNO3 And shows geometrical isomerism. The IUPAC nomenclature of X Is: JEE Main 2020 (09 Jan Shift 1) JEE Main Previous Year Paper (1) Hexaaqua chromium(III) chloride (2) Tetraaquadichlorido chromium(IV) chloride dihydrate (3) Dichloridotetraaqua chromium(IV) chloride (4) Tetraaquadichlorido chromium(III) chloride dihydrate dihydrate Q41. [Pd(F)(Cl)(Br)(I)]2− has n number of geometrical isomers. Then, the spin-only magnetic moment and crystal field stabilization energy [CFSE] of [Fe(CN)6]n−6 , respectively, are: [Note: Ignore the pairing energy] (1) 2.84 BM and −16Δ0 (2) 5.92 BM and 0 (3) 1.73 BM and −2.0Δ0 (4) 0 BM and −2.4Δ0

Q42.The compound A in the following reactions is: (i) CH3 MgBr /H2O (i) O3 −−A → B → C + D (ii) Conc. H2 SO4 /Δ (ii) Zn /H2O (1) (2) (3) (4)

Q42.When neopentyl alcohol is heated with an acid, it slowly converted into an 85 : 15 mixture of alkenes A and B, respectively. What are these alkenes? (1) (2) (3) (4) Q43. [P] on treatment with Br2 / FeBr3 in CCl4 produced a single isomer C8H7O2 Br wile heating [P] with sodalime gives toluene. The compound [P] is: (1) (2) (3) (4)

Q43.The species that has a spin-only magnetic moment of 5. 9 BM, is : ( Td =tetrahedral) (1) [Ni(CN)4]2− (square planar) (2) [NiCl4]2−(Td) (3) Ni(CO)4(Td) (4) [MnBr4]2−(Td) JEE Main 2020 (06 Sep Shift 1) JEE Main Previous Year Paper

Q43. Three isomers A, B and C (mol. formula C8H11N ) give the following results: Dianotization (i) Hydrolyds −−A and C → P + Q → R (product of A) + S (product of C) (ii) acidation(KMnO4+H+) R has lower boiling point than S C6H5 SO2 Cl −B → alkali-insoluble product JEE Main 2020 (03 Sep Shift 2) JEE Main Previous Year Paper A, B and C, respectively are: (1) (2) (3) (4)

Q43.Two compounds A and B with same molecular formula (C3H6O) undergo Grignard reaction with methylmagnesium bromide to give products C and D . Products C and D show following chemical tests. JEE Main 2020 (02 Sep Shift 2) JEE Main Previous Year Paper Test C D Ceric Positive Positive ammonium nitrate Test Turbidity obtained after Turbidity obtained Lucas Test five minutes Immediately Iodoform Test Positive Negative C and D respectively are (1) (2) (3) (4)

Q43.The correct order of the calculated spin-only magnetic moments of complexes (A) to (D) is: (A) Ni(CO)4 (B) [Ni(H2O)6]Cl2 (C) Na2[Ni(CN)4] (D) PdCl2(PPh3)2 (1) (A) ≈(C) < (B) ≈(D) (2) (C) < (D) < (B) < (A) (3) (C) ≈(D) < (B) < (A) (4) (A) ≈(C) ≈(D) < (B)

Q43.The major product [C] of the following reaction sequence will be : JEE Main 2020 (04 Sep Shift 2) JEE Main Previous Year Paper (1) (2) (3) (4)

Q44.The major aromatic product C in the following reaction sequence will be : (1) (2) (3) (4)

Q44.An organic compound [A], molecular formula C10H20O2 was hydrolyzed with dilute sulphuric acid to given a carboxylic acid [B] and an alcohol [C]. Oxidation of [C] with CrO3 −H2 SO4 produced [B]. Which of the following structures are not possible for [A] (1) (2) (3) CH3 CH2 CH2 COOCH2 CH2 CH2 CH3 (4) (CH3)3 −C −COOCH2 C(CH3)3

Q45.A chemist has 4 samples of artificial sweetener A, B, C and D . To identify these samples, he performed certain experiments and noted the following observations: (i) A and D both form blue-violet colour with ninhydrin. (ii) Lassaigne extract of C gives positive AgNO3 test and negative Fe4[Fe(CN)6]3 test. (iii) Lassaigne extract of B and D gives positive sodium nitroprusside test. Based on these observations which option is correct? (1) A : Aspartame; B : Saccharin; C : Sucralose; D : (2) A : Alitame; B : Saccharin; C : Aspartame; D : Alitame Sucralose (3) A : Saccharin; B : Alitame; C : Sucralose; D : (4) A : Aspartame; B : Alitame; C : Saccharin; D : Aspartame Sucralose

Q46.A soft drink was bottled with a partial pressure of CO2 of 3 bar over the liquid at room temperature. The partial pressure of CO2 over the solution approaches a value of 30 bar when 44 g of CO2 is dissolved in 1 kg of water at room temperature. The approximate pH of the soft drink is ___________ ×10−1 . (First dissociation constant of H2 CO3 = 4. 0 × 10−7; log 2 = 0. 3; density of the soft drink = 1 g mL−1 ) JEE Main 2020 (05 Sep Shift 1) JEE Main Previous Year Paper

Q46.The ratio of the mass percentages of ' C & H ' and ' C & O' of a saturated acyclic organic compound ' X ' are 4 : 1 and 3 : 4 respectively. Then, the moles of oxygen gas required for complete combustion of two moles of organic compound ' X' is_______