Practice Questions

Q50.Out of following isomeric forms of uracil, which one is present in RNA? (1) (2) (3) (4)

Q50.Which of the following is correct structure of α-anomer of maltose? JEE Main 2021 (25 Feb Shift 2) JEE Main Previous Year Paper (1) (2) (3) (4)

Q50.Seliwanoff test and Xanthoproteic test are used for the identification of _ and _ respectively. (1) aldoses, ketoses (2) ketoses, proteins (3) proteins, ketoses (4) ketoses, aldoses

Q50.Which one of the following compounds contains β −C1 −C4 glycosidic linkage ? (1) Sucrose (2) Amylose (3) Lactose (4) Maltose

Q51.Consider the complete combustion of butane, the amount of butane utilized to produce 72 . 0 g of water is ______ × 10-1 g. (in nearest integer) JEE Main 2021 (25 Jul Shift 1) JEE Main Previous Year Paper

Q51.The density of NaOH solution is 1. 2 g cm−3. The molality of this solution is m (Round off to the Nearest Integer): [Use : Atomic masses : Na : 23. 0u O : 16. 0u H : 1. 0u Density of H2O : 1. 0 g cm−3]

Q51. Ge (Z = 32) in its ground state electronic configuration has x completely filled orbitals with ml = 0. The value of x is __________ .

Q51.The reaction that occurs in a breath analyser, a device used to determine the alcohol level in a person's blood stream is 2 K2 Cr2 O7 + 8H2 SO4 + 3C2H6O →2 Cr2 (SO4)3 + 3C2H4O2 + 2 K2 SO4 + 11H2O If the rate of appearance of Cr2 (SO4)3 is 2. 67 mol min−1 at a particular time, the rate of disappearance of C2H6O at the same time is mol min−1. (Nearest integer) Q52. 1 kg of 0. 75 molal aqueous solution of sucrose can be cooled up to −4°C before freezing. The amount of ice (in g ) that will be separated out is ___________. (Nearest integer) [Given : Kf(H2O) = 1. 86 K kg mol−1 ]

Q51.An aqueous KCl solution of density 1. 20 g mL−1 has a molality of 3. 30 mol kg−1 . The molarity of the solution in molL−1 is____.(The Nearest integer) [ Molar mass of KCl = 74. 5 g]

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 formula of a gaseous hydrocarbon which requires 6 times of its own volume of O2 for complete oxidation and produces 4 times its own volume of CO2 is CxHy. The value of y is ________. Q52. 1. 86 g of aniline completely reacts to form acetanilide. 10% of the product is lost during purification. Amount of acetanilide obtained after purification (in g) is ___________ ×10−2.

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)

Q51.The wavelength of electrons accelerated from rest through a potential difference of 40 kV is X × 10−12 m. The value of x is. (Nearest integer) Given: Mass of electron = 9. 1 × 10−31 kg Charge on an electron = 1. 6 × 10−19C Planck's constant = 6. 63 × 10−34 Js

Q51.Methylation of 10 g of benzene gave 9. 2 g of toluene. Calculate the percentage yield of toluene (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.When 35 mL of 0. 15 M lead nitrate solution is mixed with 20 mL of 0. 12 M chromic sulphate solution, ____________ ×10−5 moles of lead sulphate precipitate out. (Round off to the Nearest Integer).

Q51. In the above reaction, 3. 9 g of benzene on nitration gives 4. 92 g of nitrobenzene. The percentage yield of nitrobenzene in the above reaction is _________ %. (Round off to the Nearest Integer). (Given atomic mass : C : 12. 0 u, H : 1. 0 u O : 16. 0 u, N : 14. 0 u )

Q51. Consider the above reaction. The percentage yield of amide product is (Round off to the Nearest Integer). (Given : Atomic mass : C : 12. 0u, H : 1. 0u N : 14. 0u, O : 16. 0u, Cl : 35. 5u)

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)

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.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.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.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 reaction of cyanamide, NH2 CN(s) with oxygen was run in a bomb calorimeter and ΔU was found to be −742. 24 kJ mol−1 . The magnitude of ΔH298 for the reaction NH2 CN(s) + 23 O2(g) →N2(g) + O2(g) + H2O(l) is kJ . (Rounded off to the nearest integer) [Assume ideal gases and R = 8. 314 J mol−1 K−1 ]

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