Practice Questions

Q55.Consider the two different first order reactions given below A + B →C (Reaction 1 ) P →Q (Reaction 2) The ratio of the half life of Reaction 1 : Reaction 2 is 5 : 2. If t1 and t2 represent the time taken to complete 2/3rd and 45th of Reaction 1 and Reaction 2, respectively, then the value of the ratio t1 : t2 is ______ ×10−1 (nearest integer). [Given : log10(3) = 0.477 and log10(5) = 0.699]

Q55.The values of conductivity of some materials at 298 .15 K in Sm−1 are 2 .1 × 103, 1 .0 × 10−16, 1 .2 × 10, 3 .91 , 1 .5 × 10−2, 1 × 10−7, 1 .0 × 103. The number of conductors among the materials is _____.

Q55.The following concentrations were observed at 500 K for the formation of NH3 from N2 and H2 . At equilibrium : [N2] = 2 × 10−2M, [H2] = 3 × 10−2M and [NH3] = 1. 5 × 10−2M. Equilibrium constant for the reaction is ______.

Q55.Consider the dissociation of the weak acid HX as given below HX(aq) ⇌H+(aq) + X−(aq), Ka = 1.2 × 10−5 [Ka : dissociation constant ] The osmotic pressure of 0.03M aqueous solution of HX at 300 K is _______ ×10−2 bar (nearest integer). [Given : R = 0.083 Lbarmol−1 K−1 ]

Q55.Number of optical isomers possible for 2 – chlorobutane ........

Q56.Among the given organic compounds, the total number of aromatic compounds is JEE Main 2024 (27 Jan Shift 1) JEE Main Previous Year Paper Q57. 3−Methylhex-2-ene on reaction with HBr in presence of peroxide forms an addition product (A). The number of possible stereoisomers for ' A ' is ________.

Q56.If 50 mL of 0. 5M oxalic acid is required to neutralise 25 mL of NaOH solution, the amount of NaOH in 50 mL of given NaOH solution is_______g. JEE Main 2024 (29 Jan Shift 2) JEE Main Previous Year Paper

Q56.The standard reduction potentials at 298 K for the following half cells are given below : Cr2O2−7 + 14H+ + 6e−→2Cr3+ + 7H2O, E∘= 1.33 V Fe3+(aq) + 3e−→Fe E∘= −0.04 V Ni2+(aq) + 2e−→Ni E∘= −0.25 V Consider the given electrochemical reactions, The Ag+(aq) + e−→Ag E∘= 0.80 V Au3+(aq) + 3e−→Au E∘= 1.40 V number of metal(s) which will be oxidized be Cr2O2−7 , in aqueous solution is ______

Q56.NO2 required for a reaction is produced by decomposition of N2O5 in CCl4 as by equation 2N2O5 ( g ) →4NO2 ( g ) + O2 ( g ) The initial concentration of N2O5 is 3 mol L-1 and it is 2 . 75 mol L-1 after 30 minutes. The rate of formation of NO2 is x × 10-3 mol L-1 min-1, value of x is ________.

Q56.The amount of electricity in Coulomb required for the oxidation of 1 mol of H2O to O2 is ______ × 105C .

Q56.One Faraday of electricity liberates x × 10 – 1 gram atom of copper from copper sulphate, x is______.

Q56.Total number of deactivating groups in aromatic electrophilic substitution reaction among the following is JEE Main 2024 (01 Feb Shift 1) JEE Main Previous Year Paper

Q56.For a certain thermochemical reaction M →N at T = 400 K, ΔHo = 77 . 2 kJ mol-1, ΔSo = 122JK-1, log equilibrium constant ( logK ) is - _____ × 10-1.

Q56.The vapour pressure of pure benzene and methyl benzene at 27∘C is given as 80 Torr and 24 Torr, respectively. The mole fraction of methyl benzene in vapour phase, in equilibrium with an equimolar mixture of those two liquids (ideal solution) at the same temperature is _______ ×10−2 (nearest integer)

Q56.During Kinetic study of reaction 2A + B →C + D , the following results were obtained : A [M] B [M] initial rate of formation of D I 0.1 0.1 6.0 × 10−3 II 0.3 0.2 7.20 × 10−2 Based on above data, overall order of the reaction is III 0.3 0.4 2.88 × 10−1 IV 0.4 0.1 2.40 × 10−2 ______

Q56.Consider the following reaction, the rate expression of which is given below A + B →C rate = k[A]1/2[ B]1/2 The reaction is initiated by taking 1M concentration of A and B each. If the rate constant (k) is 4.6 × 10−2 s−1 , then the time taken for A to become 0.1M is ______ sec. (nearest integer)

Q56.Among VO+2 , MnO−4 and Cr2O2−7 , the spin-only magnetic moment value of the species with least oxidising ability is ______ BM (Nearest integer). (Given atomic member V = 23, Mn = 25, Cr = 24) JEE Main 2024 (06 Apr Shift 2) JEE Main Previous Year Paper

Q56.r = kA for a reaction, 50% of A is decomposed in 120 minutes. The time taken for 90% decomposition of A is ______ minutes.

Q56.Consider the following reaction A + B →C The time taken for A to become 1/4th of its initial concentration is twice the time taken to become 1/2 of the same. Also, when the change of concentration of B is plotted against time, the resulting graph gives a straight JEE Main 2024 (08 Apr Shift 1) JEE Main Previous Year Paper line with a negative slope and a positive intercept on the concentration axis. The overall order of the reaction is _______

Q56.Time required for 99.9% completion of a first order reaction is _______ times the time required for completion of 90% reaction.(nearest integer)

Q56.A solution of H2 SO4 is 31. 4% H2 SO4 by mass and has a density of 1. 25 g/ mL. The molarity of the H2 SO4 solution is M (nearest integer) [Given molar mass of H2 SO4 = 98 g mol−1 ]

Q56.Consider the following single step reaction in gas phase at constant temperature. 2 A(g) + B(g) →C(g) The initial rate of the reaction is recorded as r1 when the reaction starts with 1.5 atm pressure of A and 0.7 atm pressure of B . After some time, the rate r2 is recorded when the pressure of C becomes 0.5 atm. The ratio r1 : r2 is ______ ×10−1 . (Nearest integer) JEE Main 2024 (05 Apr Shift 2) JEE Main Previous Year Paper

Q56.A solution is prepared by adding 1 mole ethyl alcohol in 9 mole water. The mass percent of solute in the solution is ________ (Integer answer) (Given : Molar mass in gmol−1 Ethyl alcohol : 46 water: 18)

Q57.Number of carbocations from the following that are not stabilized by hyperconjugation is _______

Q57.Molality of an aqueous solution of urea is 4.44 m. Mole fraction of urea in solution is x × 10−3 . Value of x is - (Integer answer)