Practice Questions

Q32.When gypsum is heated to 393K, it forms: (1) Anhydrous CaSO4 (2) CaSO4 ⋅5H2O (3) CaSO4 ⋅0.5H2O (4) Dead burnt plaster

Q32.The radius of the second Bohr orbit, in terms of the Bohr radius, a0, in Li2+ is: (1) 2a0 (2) 4a0 3 9 (3) 4a0 (4) 2a0 3 9

Q33.The incorrect statement(s) among (a) – (d) regarding acid rain is (are): a) It can corrode water pipes (b) It can damage structures made up of stone. (c) It cannot cause respiratory ailments in animals (d) It is not harmful for trees (1) (a), (c) and (d) (2) (c) only (3) (a), (b) and (d) (4) (c) and (d)

Q33.The metal mainly used in devising photoelectric cells is : (1) Na (2) Li (3) Rb (4) Cs

Q34.A set of solutions is prepared using 180 g of water as a solvent and 10 g of different non-volatile solutes A, B and C. The relative lowering of vapour pressure in the presence of these solutes are in the order [Given, molar mass of A = 100 g mol−1 ; B = 200 g mol−1 ; C = 10, 000 g mol−1 ] (1) B > C > A (2) C > B > A (3) A > B > C (4) A > C > B

Q34.Thermal power plants can lead to : (1) Acid rain (2) Blue baby syndrome (3) Ozone layer depletion (4) Eutrophication

Q34.For the reaction 2A + 3B + 32 C →3P , which statement is correct? (1) dnA dt = 32 dnBdt = 34 dnCdt (2) dnAdt = dnBdt = dnCdt (3) dnA dt = 23 dnBdt = 43 dnCdt (4) dnAdt = 23 dnBdt = 34 dnCdt

Q35.Among the gases (a) −(e), the gases that cause greenhouse effect are: (a)CO2 (b)H2O (c)CFCs (d)O2 (e)O3 (1) (a), (b), (c) and (d) (2) (a), (b), (c) and (e) (3) (a) and (d) (4) (a), (c), (d) and (e)

Q35.The processes of calcination and roasting in metallurgical industries, respectively, can lead to : (1) Global warming and photochemical smog (2) Global warming and acid rain (3) Photochemical smog and ozone layer depletion (4) Photochemical smog and global warming Q36. 250 mL of a waste solution obtained from the workshop of a goldsmith contains 0. 1 M AgNO3 and 0. 1M AuCl. The solution was electrolyzed at 2 V by passing a current of 1 A for 15 minutes. The metal/metals electrodeposited will be : (E0Ag+/Ag = 0. 80V, E0Au+/Au = 1. 69V) (1) only gold (2) silver and gold in proportion to their atomic weights (3) only silver (4) silver and gold in equal mass proportion

Q36.The element that can be refined by distillation is : (1) nickel (2) zinc (3) tin (4) gallium

Q36.The number of sp2 hybrid orbitals in a molecule of benzene is: (1) 24 (2) 6 (3) 18 (4) 12

Q37.Match the following: (i) Foam (a) smoke (ii) Gel (b) cell fluid (iii) Aerosol (c) jellies (iv) Emulsion (d) rubber (e) froth (f) milk (1) (i) – (b), (ii) – (c), (iii) – (e), (iv) – (d) (2) (i) – (d), (ii) – (b), (iii) – (a), (iv) – (e) (3) (i) – (e), (ii) – (c), (iii) – (a), (iv) – (f) (4) (i) – (d), (ii) – (b), (iii) – (e), (iv) – (f)

Q37.The reaction of NO with N2O4 at 250 K gives : (1) N2O (2) NO2 (3) N2O3 (4) N2O5

Q37.The refining method used when the metal and the impurities have low and high melting temperatures, respectively, is (1) liquation. (2) vapour phase refining. (3) zone refining. (4) distillation.

Q38.The incorrect statement(s) among (a) - (c) is (are) : (a) W(VI) is more stable than Cr(VI). (b) in the presence of HCl, permanganate titrations provide satisfactory results. JEE Main 2020 (04 Sep Shift 2) JEE Main Previous Year Paper (c) some lanthanoid oxides can be used as phosphors (1) (b) and (c) only (2) (a) and (b) only (3) (b) only (4) (a) only

Q38.The purest form of commercial iron is: (1) pig iron (2) wrought iron (3) cast iron (4) scrap iron and pig iron

Q38.Tyndall effect is observed when : (1) The diameter of dispersed particles is much (2) The diameter of dispersed particles is much larger than the wavelength of light used. smaller than the wavelength of light used (3) The refractive index od dispersed phase is greater (4) The diameter of dispersed particles is similar to than that of the dispersion medium. the wavelength of light used.

Q39.Mischmetal is an alloy consisting mainly of : (1) Lanthanoid metals (2) actinoid and transition metals (3) lanthanoid and actinoid metals (4) actinoid metals

Q40.Boron and silicon of very high purity can be obtained through : (1) liquation (2) zone refining (3) vapour phase refining (4) electrolytic refining

Q40.Hydrogen has three isotopes (A), (B) and (C). If the number of neutron(s) in (A), (B) and (C) respectively, are (x), (y) and (z), the sum of (x), (y) and (z) is (1) 3 (2) 2 (3) 4 (4) 1

Q40.Which of the following is used for the preparation of colloids ? (1) Ostwald process (2) Van Arkel Method (3) Bredig's Arc Method (4) Mond Process

Q40.The INCORRECT statement is : (1) bronze is an alloy of copper and tin. (2) cast iron is used to manufacture wrought iron. (3) german silver is an alloy of zinc, copper and (4) brass is an alloy of copper and nickel. nickel.

Q40.The isomer(s) of [Co(NH3)4Cl2] that has/ have a Cl −Co −Cl angle of 90o, is/are: (1) meridional and trans (2) cis and trans (3) trans only (4) cis only JEE Main 2020 (09 Jan Shift 2) JEE Main Previous Year Paper

Q42.The most appropriate reagent for conversion of C2H5 CN into CH3 CH2 CH2 NH2 is : (1) NaBH4 (2) CaH2 (3) LiAlH4 (4) Na(CN) BH3

Q44.Which one of the following polymers is not obtained by condensation polymerisation ? (1) Nylon 6, 6 (2) Buna – N (3) Bakelite (4) Nylon 6