Practice Questions
280 questions across 23 years of JEE Main — find and practise any topic!
Found 280 results
Q60. M2+ + H2 S →A (Black precipitate) + by product Consider the following test for a group-IV cation. A + aqua regia →B + NOCl + S + H2O The B + KNO2 + CH3COOH →C + by product spin-only magnetic moment value of the metal complex C is ______ BM (Nearest integer)
Q61.Consider the following two statements : Statement I : For any two non-zero complex numbers z1, z2 , (|z1| + |z2|) z1 + z2 ≤2 (|z1| + |z2|), and |z1| |z2| Statement II : If x, y, z are three distinct complex numbers and a, b, c are three positive real numbers such that |y−z| a = |z−x|b = |x−y|c , then y−za2 + z−xb2 + x−yc2 = 1. Between the above two statements, (1) Statement I is correct but Statement II is (2) both Statement I and Statement II are correct. incorrect. (3) both Statement I and Statement II are incorrect. (4) Statement I is incorrect but Statement II is correct.
Q61.If z = x + iy, xy ≠0, satisfies the equation z2 + iz = 0, then z2 is equal to : (1) 9 (2) 1 (3) 4 (4) 14
Q33.A litre of buffer solution contains 0. 1 mole of each of NH3 and NH4 Cl. On the addition of 0. 02 mole of HCl by dissolving gaseous HCl , the pH of the solution is found to be _____ × 10−3 (Nearest integer) Given: pKb(NH3) = 4. 745 log 2 = 0. 301 log 3 = 0. 477 T = 298 K]
Q34.The number of species trom the following carrying a single lone pair on central atom Xenon is XeF+5 , XeO3, XeO2 F2, XeF−5 , XeO3 F2, XeOF4, XeF4
Q35.When the hydrogen ion concentration [H+]changes by a factor of 1000 , the value of pH of the solution (1) increases by 1000 units (2) decreases by 3 units (3) decreases by 2 units (4) increases by 2 units
Q35.One mole of an ideal monoatomic gas is subjected to changes as shown in the graph. The magnitude of the work done (by the system or on the system) is _______ J (nearest integer) Given : log 2 = 0.3, ln 10 = 2.3
Q35.Amongst the following, the number of species having the linear shape is XeF2, I+3 , C3O2, I−3 , CO2, SO2, BeCl2 and BCl⊖2
Q35.Gibbs energy vs T plot for the formation of oxides is given below. For the given diagram, the correct statement is- (1) At 600°C, CO cannot reduce FeO (2) At 600°C, CO can reduce ZnO (3) At 600°C, C can reduce ZnO (4) At 600°C, C can reduce FeO
Q35.But-2-yne is reacted separately with one mole of Hydrogen as shown below: Na Pd / C ← B CH3 - C ≡ C - CH3 →∆ A¯ ¯ liq NH3 +H2 Identify the incorrect statements from the options given below: A. A is more soluble than B. B. The boiling point & melting point of A are higher and lower than B respectively. C. A is more polar than B because dipole moment of A is zero. D. Br2 adds easily to B than A. (1) B and C only (2) B, C and D only (3) A, C and D only (4) A and B only
Q36.For complete combustion of ethene, C2H4( g) + 3O2( g) →2 CO2( g) + 2H2O(l) the amount of heat produced as measured in bomb calorimeter is 1406 kJ mol−1 at 300 K. The minimum value of TΔS needed to reach equilibrium is (−) kJ. (Nearest integer) Given: R = 8. 3 J K−1 mol−1
Q36.If the pKa of lactic acid is 5 , then the pH of 0. 005 M calcium lactate solution at 25° C is __________ × 10–1 (Nearest integer)
Q36.Choose the correct set of reagents for the following conversion transPh - CH = CH - CH3 → cis Ph - CH = CH - CH3 (1) Br2, alc KOH, NaNH2, NaLiqNH3 (2) Br2, alc KOH, NaNH2, H2 Lindlar Catalyst (3) Br2, aqKOH, NaNH2, H2 Lindlar Catalyst (4) Br2, aq KOH, NaNH2, NaLiqNH3
Q37.One mole of an ideal gas at 350 K is in a 2. 0 L vessel of thermally conducting walls, which are in contact with the surroundings. It undergoes isothermal reversible expansion from 2. 0 L to 3. 0 L against a constant pressure of 4 atm. The change in entropy of the surroundings (ΔS) is _____ J K–1 (Nearest integer) Given: R = 8. 314 J K−1 mol−1 . JEE Main 2023 (12 Apr Shift 1) JEE Main Previous Year Paper
Q39.The product formed in the following multistep reaction is: (1) (2) (3) (4)
Q39.The correct order for acidity of the following hydroxyl compound is (A) CH3OH (B) CH33COH (C) (D) (E) Choose the correct answer from the options given below: (1) C > E > D > B > A (2) E > D > C > B > A (3) D > E > C > A > B (4) E > C > D > A > B
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)
Q43.Following chromatogram was developed by adsorption of compound ' A ' on a 6 cm TLC glass plate. Retardation factor of the compound ' A' is _____ ×10−1 . Q44. 17 mg of a hydrocarbon (M.F. C10H16 ) takes up 8. 40 mL of the H2 gas measured at 0°C and 760 mm of Hg. Ozonolysis of the same hydrocarbon yields CH3 −C −CH3, H −C −H, H −C −CH2 −CH2 −C −C −H || || || || || O O O O O The number of double bond/s present in the hydrocarbon is
Q44.A hydrocarbon 'X' with formula C6H8 uses two moles of H2 on catalystic hydrogenation of its one mole. On ozonolysis, 'X' yields two moles of methane dicarbaldehyde. The hydrocarbon 'X' is : (1) hexa- 1, 3, 5 -triene (2) 1-methylcyclopenta- 1, 4−diene (3) cyclohexa −1, 3−diene (4) cyclohexa −1, 4−diene
Q45.The correct order of the number of unpaired electrons in the given complexes is (A) [Fe ( CN ) 3 - 6] (B) FeF6 3 - (C) CoF6 3 - (D) Cr ( oxalate 3 - ) 3 (E) Ni ( CO ) 4 Choose the correct answer from the options given below: (1) E < A < D < C < B (2) E < A < B < D < C (3) A < E, C < B < D (4) A < E < D < C < B
Q46.Solid Lead nitrate is dissolved in 1 litre of water. The solution was found to boil at 100. 15°C. When 0. 2 mol of NaCl is added to the resulting solution, it was observed that the solution froze at −0. 8°C. The solutbility product of PbCl2 formed is _____ ×10−6 at 298 K. (Nearest integer) Given : Kb = 0. 5K kg mol−1 and Kf = 1. 8 kg mol−1 . Assume molality to be equal to molarity in all cases. JEE Main 2023 (29 Jan Shift 1) JEE Main Previous Year Paper
Q46.The total number of stereoisomers for the complex [Cr ( ox ) 2ClBr] 3 – (where ox = oxalate) is (1) 3 (2) 2 (3) 4 (4) 1
Q47.L-isomer of tetrose X ( C4H8O4 ) gives positive Schiff’s test and has two chiral carbons. On acetylation ‘X’ yields triacetate. ‘X’ also undergoes following reactions. (1) (2) (3) (4) JEE Main 2023 (11 Apr Shift 1) JEE Main Previous Year Paper Q48. ‘A’ and ‘B’ in the above reactions are: (1) (2) (3) (4) Q49. 'X' (1) (2) (3) (4)
Q47.Consider the following reaction ( i ) dil . NaOH Propanal + Methanal = → Product B (ii) Δ(iii) NaCN(iv) H3O+ ( C5H8O3 ) The correct statement for product 𝐵 is. It is JEE Main 2023 (31 Jan Shift 1) JEE Main Previous Year Paper (1) optically active and adds one mole of bromine (2) racemic mixture and is neutral (3) racemic mixture and gives a gas with saturated (4) optically active alcohol and is neutrall NaHCO3 solution
Q47.Evaluate the following statements for their correctness. A. The elevation in boiling point temperature of water will be same for 0. 1 M NaCl and 0. 1 M urea. B. Azeotropic mixture boil without change in their composition. C. Osmosis always takes place from hypertonic to hypotonic solution. D. The density of 32% H2 SO4 solution having molarity 4. 09 M is approximately 1. 26 g mL–1 . E. A negatively charged sol is obtained when KI solution is added to silver nitrate solution. Choose the correct answer from the options given below: (1) B and D only (2) B, D and E only (3) A and C only (4) A, B and C only