Practice Questions

Q51.Complete combustion of 750 g of an organic compound provides 420 g of CO2 and 210 g of H2O . The percentage composition of carbon and hydrogen in organic compound is 15. 3 and ______ respectively. (Round off to the Nearest Integer)

Q51. Consider the above reaction where 6. 1 g of benzoic acid is used to get 7. 8 g of m-bromo benzoic acid. The percentage yield of the product is ___ . (Round off to the Nearest integer) [Given : Atomic masses : C = 12. 0 u, H : 1. 0 u, O : 16. 0 u, Br = 80. 0 u ]

Q51.Electromagnetic radiation of wavelength 663 nm is just sufficient to ionise the atom of metal A . The ionization energy of metal A in kJ mol−1 is ___. (Rounded-off to the nearest integer) [h = 6. 63 × 10−34 Js, c = 3. 00 × 108 ms−1, NA = 6. 02 × 1023 mol−1]

Q51.The value of magnetic quantum number of the outermost electron of Zn+ ion is _________ . (Integer answer) JEE Main 2021 (31 Aug Shift 2) JEE Main Previous Year Paper

Q51.A car tyre is filled with nitrogen gas at 35 psi at 27 °C . It will burst if pressure exceeds 40 psi. The temperature in ∘C at which the car tyre will burst is (Rounded-off to the nearest integer)

Q52.A source of monochromatic radiation wavelength 400 nm provides 1000 J of energy in 10 seconds. When this radiation falls on the surface of sodium, x × 1020 electrons are ejected per second. Assume that wavelength 400 nm is sufficient for ejection of electron from the surface of sodium metal. The value of x is ______. (Nearest integer) h = 6 . 626 × 10-34 Js

Q52.An accelerated electron has a speed of 5 × 106 ms−1 with an uncertainty of 0. 02%. The uncertainty in finding its location while in motion is x × 10−9 m. The value of x is __________. (Nearest integer) [Use mass of electron = 9. 1 × 10−31 kg, h = 6. 63 × 10−34 Js, π = 3. 14]

Q52.Complete combustion of 3 g of ethane gives x × 1022molecules of water. The value of x is ______ (Round off to the Nearest Integer). [Use : NA = 6. 023 × 1023; Atomic masses in u : C : 12. 0 ; O : 16. 0 ; H : 1. 0]

Q52.In gaseous triethyl amine the ′′−C −N −C −′′ bond angle is ____ degree.

Q52.The total number of electrons in all bonding molecular orbitals of O2−2 is ......... (Round off to the nearest integer)

Q52.A 50 watt bulb emits monochromatic red light of wavelength of 795 nm. The number of photons emitted per second by the bulb is 𝑥× 1020 . The value of 𝑥 is _____ . (Nearest integer) [Given : h = 6 . 63 × 10-34Js and 𝑐= 3 . 0 × 108 ms-1

Q52.The number of species below that have two lone pairs of electrons in their central atom is ___ (Round off to the Nearest integer) SF4, BF−4 , ClF3, AsF3, PCl5, BrF5, XeF4, SF6

Q52.For water Δvap H = 41 kJ mol−1 at 373 K and 1 bar pressure. Assuming that water vapour is an ideal gas that occupies a much larger volume than liquid water, the internal energy change during evaporation of water is (kJmol−1) : [ Use : R = 8. 3 J mol−1 K−1]

Q52.A certain gas obeys P(Vm −b) = RT. The value of ( ∂P∂Z )T is RTxb . The value of x is (Integer answer) ( Z : compressibility factor)

Q52.Number of electrons that Vanadium (Z = 23) has in p-orbitals is equal to:

Q52.The number of photons emitted by a monochromatic (single frequency) infrared range finder of power 1 mW and wavelength of 1000 nm, in 0. 1 second is x × 1013 . The value of x is (Nearest integer) (h = 6. 63 × 10−34 Js, c = 3. 00 × 108 ms−1):

Q52.A proton and a Li3 + nucleus are accelerated by the same potential. If 𝜆Li and 𝜆p denote the de Broglie + 𝜆Li wavelengths of Li3 and proton respectively, then the value of is 𝑥× 10-1. The value of x 𝜆p is _____ (Rounded off to the nearest integer) [Mass of Li3 + = 8 . 3 mass of proton]

Q52.A 6. 50 molal solution of KOH(aq. ) has a density of 1. 89 g cm−3 . The molarity of the solution is mol dm−3 . (Round off to the Nearest Integer). [Atomic masses: K : 39. 0 u; O : 16. 0 u; H : 1. 0 u]

Q52.A ball weighing 10 g is moving with a velocity of 90 m s−1. If the uncertainty in its velocity is 5%, then the uncertainty in its position is _ ×10−33 m. (Rounded off to the nearest integer) [Given: h = 6. 63 × 10−34 Js]

Q52.The number of orbitals with n = 5, m1 = +2 is ________. (Round off to the Nearest Integer).

Q52.The number of chlorine atoms in 20 mL of chlorine gas at STP is _______ 1021 . (Round off to the Nearest Integer). [Assume chlorine is an ideal gas at STP R = 0. 083 L bar mol−1 K−1, NA = 6. 023 × 1023]

Q52.The mole fraction of a solute in a 100 molal aqueous solution ________ ×10−2. (Round off to the Nearest Integer). [Given : Atomic masses: H : 1. 0 u, O : 16. 0 u ]

Q52.For a given chemical reaction A →B at 300 K the free energy change is −49. 4 kJ mol−1 and the enthalpy of reaction is 51. 4 kJ mol−1. The entropy change of the reaction is _________ JK−1 mol−1. Q53. 4 g equimolar mixture of NaOH and Na2 CO3 contains xg of NaOH and yg of Na2 CO3. The value of x is g. (Nearest integer)

Q52.According to molecular orbital theory, the number of unpaired electron(s) in O22 - is _________ .

Q52.Five moles of an ideal gas at 293 K is expanded isothermally from an initial pressure of 2. 1 MPa to 1. 3 MPa against at constant external pressure 4. 3 MPa. The heat transferred in this process is ___ kJmol−1 . (Rounded-off to the nearest integer) [ Use R = 8. 314 J mol−1 K−1 ]