Practice Questions

Q51.The molarity of 1L orthophosphoric acid H3PO4 having 70% purity by weight (specific gravity 1 .54 g cm−3 ) is ______ M. (Molar mass of H3PO4 = 98 g mol-1) o

Q52.The ionization energy of sodium in kJ mol – 1 . If electromagnetic radiation of wavelength 242 nm is just sufficient to ionize sodium atom is ______.(nearest integer)

Q52.Total number of electrons present in (π∗) molecular orbitals of O2, O2+ and O−2 is _______.

Q52.Number of molecules from the following which are exceptions to octet rule is ______ CO2, NO2, H2SO4, BF3, CH4, SiF4, ClO2, PCl5, BeF2, C2H6, CHCl3, CBr4

Q52.The number of electrons present in all the completely filled subshells having n = 4 and s = + 12 is ____ (Where n = principal quantum number and s = spin quantum number)

Q52.The total number of species from the following in which one unpaired electron is present, is _______ N2, O2, C−2 , O−2 , O2−2 , H+2 , CN−, He+2

Q52.If IUPAC name of an element is "Unununnium" then the element belongs to nth group of periodic table. The value of n is _______.

Q52.Number of molecules/species from the following having one unpaired electron is O2, O−12 , NO, CN−1, O2−2

Q52.Lowest Oxidation number of an atom in a compound A2B is -2 . The number of an electron in its valence shell is

Q52.Number of molecules having bond order 2 from the following molecules is ________ C2, O2, Be2, Li2, Ne2, N2, He2 Q53. Δvap H⊖ for water is +40.79 kJ mol−1 at 1 bar and 100∘C. Change in internal energy for this vapourisation under same condition is kJmol−1 . (Integer answer) (Given R = 8.3JK−1 mol−1 ) JEE Main 2024 (08 Apr Shift 2) JEE Main Previous Year Paper

Q52.Two reactions are given below: 3 ( s ) , 𝛥Ho = - 822 kJ / mol 2Fe ( s ) + 2O2 ( g ) →Fe2O3 1 C ( s ) + 2O2 ( g ) →CO ( g ) , 𝛥Ho = - 110 kJ / mol Then enthalpy change for following reaction 3C ( s ) + Fe2O3 ( s ) →2Fe ( s ) + 3CO ( g )

Q52.The value of Rydberg constant (RH) is 2.18 × 10−18 J. The velocity of electron having mass 9.1 × 10−31 kg in Bohr's first orbit of hydrogen atom = _______ ×105 ms−1 (nearest integer).

Q52.The total number of 'Sigma' and Pi bonds in 2-formylhex-4-enoic acid is

Q52.For a certain reaction at 300 K, K = 10, then ΔG° for the same reaction is – ________ × 10-1 kJ mol-1 . (Given R = 8 . 314JK-1 mol-1)

Q52.Number of molecules from the following which can exhibit hydrogen bonding is _______ (nearest integer) –5

Q52.Number of compounds from the following with zero dipole moment is ______ HF, H2, H2 S, CO2, NH3, BF3, CH4, CHCl3, SiF4, H2O, BeF2

Q52.A diatomic molecule has a dipole moment of 1 .2 D. If the bond distance is 1 A, then fractional charge on each atom is _____ × 10−1 esu. (Given 1D = 10−18 esu cm) JEE Main 2024 (31 Jan Shift 2) JEE Main Previous Year Paper

Q52.Number of compounds / species from the following with non-zero dipole moment is ______ BeCl2, BCl3, NF3, XeF4, CCl4, H2O, H2 S, HBr, CO2, H2, HCl

Q53.The pH of an aqueous solution containing 1M benzoic acid pKa = 4 . 20 and 1M sodium benzoate is 4 . 5 . The volume of benzoic acid solution in 300 mL of this buffer solution is __________mL.

Q53.The enthalpy of formation of ethane (C2H6) from ethylene by addition of hydrogen where the bond-energies of C −H, C −C, C = C, H −H are 414 kJ, 347 kJ, 615 kJ and 435 kJ respectively is kJ

Q53.An amine (X) is prepared by ammonolysis of benzyl chloride. On adding p-toluenesulphonyl chloride to it the solution remains clear. Molar mass of the amine (X) formed is ______ gmol−1 . (Given molar mass in gmol−1C : 12, H : 1, O : 16, N : 14)

Q53.If 5 moles of an ideal gas expands from 10L to a volume of 100L at 300K under isothermal and reversible condition then work, w, is −x J. The value of x is - _______. (Given R = 8 .314 J K-1 mol-1)

Q53.The number of molecules/ion/s having trigonal bipyramidal shape is …….. . PF5, BrF5, PCl5, PtCl4 2 - , BF3, Fe(CO ) 5

Q53.When equal volume of 1MHCl and 1MH2SO4 are separately neutralised by excess volume of 1M NaOH solution. x and y kJ of heat is liberated respectively. The value of y/x is _______

Q53.Combustion of 1 mole of benzene is expressed at C6H6(l) + 152 O2( g) →6CO2( g) + 3H2O(l). The standard enthalpy of combustion of 2 mol of benzene is −′x′kJ. x = ______ Given: 1. standard Enthalpy of formation of 1 mol of C6H6(l), for the reaction 6C (graphite) +3H2( g) →C6H6(l) is 48.5 kJ mol−1 . 2. Standard Enthalpy of formation of 1 mol of CO2( g), for the reaction C (graphite) +O2( g) →CO2( g) is −393.5 kJ mol−1 . 3. Standard and Enthalpy of formation of 1 mol of H2O(l), for the reaction H2( g) + 12 O2( g) →H2O(l) is −286 kJ mol−1 .