Practice Questions

Q51.The total number of molccules with zero dipole moment among CH4, BF3, H2O, HF, NH3, CO2 and SO2 is ______.

Q51.Number of spectral lines obtained in He+ spectra, when an electron makes transition from fifth excited state to first excited state will be

Q51.Consider the following reaction: 3PbCl2 + 2NH43PO4 →Pb3PO42 + 6NH4Cl If 72 mmol PbCl2 is mixed with 50 mmol of NH43PO4, then amount of Pb3PO42 formed in mmol. (nearest integer)

Q51.Wavenumber for a radiation having 5800Ã … wavelength is x × 10 cm−1 . The value of x is ________ (Integer answer)

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

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

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 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.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.For hydrogen atom, energy of an electron in first excited state is −3.4eV, K. E. of the same electron of hydrogen atom is xeV . Value of x is ______ ×10−1eV . (Nearest integer)

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

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 number of species from the following which are paramagnetic and with bond order equal to one is H2, He+2 , O+2 , N2−2 , O2−2 , F2, Ne+2 , B2

Q52.Lowest Oxidation number of an atom in a compound A2B is -2 . The number of an electron in its valence shell 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/species from the following having one unpaired electron is O2, O−12 , NO, CN−1, O2−2

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

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

Q53.An ideal gas, Cv = 2 R, is expanded adiabatically against a constant pressure of 1 atm untill it doubles in volume. If the initial temperature and pressure is 298 K and 5 atm, respectively then the final temperature is – _______ K (nearest integer). [ Cv is the molar heat capacity at constant volume] JEE Main 2024 (06 Apr Shift 1) JEE Main Previous Year Paper ′′ −

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.