Practice Questions

Q71.The molar mass of the water insoluble product formed from the fusion of chromite ore (FeCr2O4) with Na2CO3 in presence of O2 is _______ gmol−1 .

Q71.Xg of benzoic acid on reaction with aq NaHCO3 released CO2 that occupied 11.2 L volume at STP. X is _____ g.

Q71.In Carius method of estimation of halogen, 0.25 g of an organic compound gave 0.15 g of silver bromide (AgBr). The percentage of Bromine in the organic compound is … … ×10−1% (Nearest integer). (Given : Molar mass of Ag is 108 and Br is 80 g mol−1 )

Q71.The compound with molecular formula C6H6 , which gives only one monobromo derivative and takes up four moles of hydrogen per mole for complete hydrogenation has ________ = electrons. 2025 (22 Jan Shift 2) JEE Main Previous Year Paper Q72.20 mL of 2 M NaOH solution is added to 400 mL of 0.5 M NaOH solution. The final concentration of the solution is _______ ×10−2M. (Nearest integer)

Q72. A → B The molecule A changes into its isomeric form B by following a first order kinetics at a temperature of 1000 K . If the energy barrier with respect to reactant energy for such isomeric transformation is 191.48 kJ mol−1 and the frequency factor is 1020 , the time required for 50% molecules of A to become B is _________ picoseconds (nearest integer). [R = 8.314 J K−1 mol−1]

Q72.Isomeric hydrocarbons → negative Baeyer's test (Molecular formula C9H12 ) The total number of isomers from above with four different non-aliphatic substitution sites is -

Q72.A compound ' X′ absorbs 2 moles of hydrogen and ' X′ upon oxidation with KMnO4 ∣H+ gives The total number of σ bonds present in the compound ' X′ is______

Q72.A group 15 element forms dπ −dπ bond with transition metals. It also forms hydride, which is a strongest base among the hydrides of other group members that form dπ −dπ bond. The atomic number of the element is ____.

Q72.The observed and normal molar masses of compound MX2 are 65.6 and 164 respectively. The percent degree of ionisation of MX2 is … … %. (Nearest integer)

Q72.For the thermal decomposition of N2O5( g) at constant volume, the following table can be formed, for the reaction mentioned below. 2 N2O5( g) →2 N2O4( g) + O2( g) x = … × 10−3 atm [nearest integer] Given : Rate constant for the reaction is 4.606 × 10−2 s−1 .

Q72.Consider the following reaction occurring in the blast furnace: Fe3O4( s) + 4CO(g) →3Fe(l) + 4CO2( g) ' x ' kg of iron is produced when 2.32 × 103 kgFe3O4 and 2.8 × 102 kgCO are brought together in the furnace. The value of ' x ' is _____. (nearest integer) Given: molar mass of Fe3O4 = 232 g mol−1 molar mass of CO = 28 g mol−1 molar mass of Fe = 56 g mol−1} Q73. 37.8 g N2O5 was taken in a 1 L reaction vessel and allowed to undergo the following reaction at 500 K 2 N2O5( g) ⇌2 N2O4( g) + O2( g) The total pressure at equilibrium was found to be 18.65 bar. Then, Kp = ______ ×10−2 [nearest integer] Assume N2O5 to behave ideally under these conditions. Given: R = 0.082 bar Lmol−1 K−1

Q72.Given below are some nitrogen containing compounds ∣∣∣ 2025 (29 Jan Shift 1) JEE Main Previous Year Paper Each of them is treated with HCl separately. 1.0 g of the most basic compound will consume _______ mg of HCl. (Given molar mass in gmol−1C : 12, H : 1, O : 16, Cl : 35.5)

Q72.The molarity of a 70% (mass / mass) aqueous solution of a monobasic acid (X) is __________ ×10−1 M(Nearest integer) [Given: Density of aqueous solution of (X) is 1.25 g mL−1 Molar mass of the acid is 70 g mol−1 ] 2025 (28 Jan Shift 1) JEE Main Previous Year Paper

Q73.When 81.0 g of aluminium is allowed to react with 128.0 g of oxygen gas, the mass of aluminium oxide produced in grams is_______ - (Nearest integer) Given : Molar mass of Al is 27.0 g mol−1 Molar mass of O is 16.0 g mol−1

Q73. Consider the following sequence of reactions : Molar mass of the product formed (A) is _______ gmol−1 .

Q73.Consider the following low-spin complexes K3 [Co(NO2)6], K4 [Fe(CN)6], K3 [Fe(CN)6], Cuu2 [Fe(CN)6] and Zn2 [Fe(CN)6] The sum of the spin-only magnetic moment values of complexes having yellow colour is. _____ B.M. (answer in nearest integer)

Q73.Consider the following cases of standard enthalpy of reaction (ΔH∘r in kJmol−1) 7 C2H6( g) + O2( g) →2CO2( g) + 3H2O(l)ΔH∘1 = −1550 2 C (graphite) + O2( g) →CO2( g) ΔH∘2 = −393.5 The magnitude of ΔH∘fC2H6( g) is _______ 1 H2( g) + O2( g) →H2O(l) ΔH∘3 = −286 2 kJmol−1 (Nearest integer).

Q73.Total number of molecules/species from following which will be paramagnetic is ______ O2, O+2 , O−2 , NO, NO2, CO, K2 [NiCl4], [Co(NH3)6]Cl3, K2 [Ni(CN)4]

Q73.The sum of sigma (σ) and pi (π) bonds in Hex-1,3-dien-5-yne is _______. Q74. 0.1 mole of compound ' S ' will weigh _______ g. (Given molar mass in gmol−1C : 12, H : 1, O : 16)

Q73.Consider a complex reaction taking place in three steps with rate constants k1, k2 and k3 respectively. The overall rate constant k is given by the expression k = . If the activation energies of the three steps are √k1k3k2 60,30 and 10 kJ mol−1 respectively, then the overall energy of activation in kJmol−1 is … … . (Nearest integer)

Q73.Consider the following sequence of reactions: 11.25 mg of chlorobenzene will produce __________ ×10−1mg of product B . (Consider the reactions result in complete conversion.) [Given molar mass of C, H, O, N and Cl as 12, 1, 16, 14 and 35.5 g mol−1 respectively]

Q73.During " S " estimation, 160 mg of an organic compound gives 466 mg of barium sulphate. The percentage of – Sulphur in the given compound is _______ %. (Given molar mass in gmol−1 of Ba : 137, S : 32, O : 16 )

Q74.If 1 mM solution of ethylamine produces pH = 9, then the ionization constant (Kb) of ethylamine is 10−x . The value of x is ______ (nearest integer). [The degree of ionization of ethylamine can be neglected with respect to unity.]

Q74.Among the following cations, the number of cations which will give characteristic precipitate in their identification tests with K4 [Fe(CN)6] is _____. Cu2+, Fe3+, Ba2+, Ca2+, NH+4 , Mg2+, Zn2+

Q74.The bond dissociation enthalpy of X2ΔHbond calculated from the given data is kJmol−1 . (Nearest M+X−(s) →M+(g) + X−(g)ΔH∗lattice = 800 kJ mol−1 integer) M( s) →M( g)ΔH∘sub = 100 kJ mol−1 M( g) →M+(g) + e−(g)ΔHi = 500 kJ mol−1 X( g) + e−(g) →X−(g)ΔH∗eg = −300 kJ mol−1 M( s) + 12 X2( g) →M+X−(s)ΔH∘f = −400 kJ mol−1 [Given : M+X− is a pure ionic compound and X forms a diatomic molecule X2 in gaseous state] 2025 (23 Jan Shift 2) JEE Main Previous Year Paper