Practice Questions

Q38.The conversion of hydroxyapatite occurs due to presence of F− ions in water. The correct formula of hydroxyapatite is: (1) [Ca3 (PO4)2 ⋅CaF2] (2) [3 Ca3 (PO4)2 ⋅Ca(OH)2] (3) [3 Ca3 (PO4)2 ⋅CaF2] (4) [3 Ca(OH)2 ⋅CaF2]

Q38.The nature of charge on resulting colloidal particles when FeCl3 is added to excess of hot water is: (1) positive (2) sometimes positive and sometimes negative (3) neutral (4) negative

Q38.The green house gas/es is (are): (A) Carbon dioxide (B) Oxygen (C) Water vapour (D) Methane Choose the most appropriate answer from the options given below: (1) (A) and (C) only (2) (A) only (3) (A), (C) and (D) only (4) (A) and (B) only

Q39.Which refining process is generally used in the purification of low melting metals? (1) Chromatographic method (2) Electrolysis (3) Zone refining (4) Liquation

Q39.In Carius method, halogen containing organic compound is heated with fuming nitric acid in the presence of: (1) HNO3 (2) AgNO3 (3) CuSO4 (4) BaSO4

Q39.The deposition of X and Y on ground surfaces is referred as wet and dry depositions, respectively. X and Y are : (1) X = CO2 , Y = SO2 (2) X = Ammonium salts Y = SO2 (3) X = Ammonium saltsY = CO2 (4) X = SO2 Y = Ammonium salts

Q39.The type of pollution that gets increased during the daytime and in the presence of O3 is : (1) Reducing smog (2) Oxidising smog (3) Global warming (4) Acid rain

Q39.Which one of the following statements is NOT correct? (1) Eutrophication indicates that water body is (2) The dissolved oxygen concentration below polluted 6 ppm inhibits fish growth (3) Eutrophication leads to increase in the oxygen (4) Eutrophication leads to anaerobic conditions level in water

Q39.The water having more dissolved O2 is : (1) boiling water (2) water at 80°C (3) polluted water (4) water at 4°C

Q39.In Freundlich adsorption isotherm, slope of AB line is: 1 1 (1) with = 0 to 1 (2) n with n = 0 . 1 to 0 . 5 n n (3) log1 with n < 1 (4) logn with n > 1 n

Q39.The chemical that is added to reduce the melting point of the reaction mixture during the extraction of aluminium is: (1) Cryolite (2) Bauxite (3) Calamine (4) Kaolite

Q40.The presence of ozone in troposphere: (1) protects us from the UV radiation (2) protects us from greenhouse effect (3) protects us from the X-ray radiation (4) generates photochemical smog

Q40.Calamine and Malachite, respectively, are the ores of : (1) Copper and Iron (2) Zinc and Copper (3) Aluminium and Zinc (4) Nickel and Aluminium

Q40.Which of the following statement(s) is (are) incorrect reason for eutrophication? (A) excess usage of fertilisers (B) excess usage of detergents (C) dense plant population in water bodies (D) lack of nutrients in water bodies that prevent plant growth Choose the most appropriate answer from the options given below : (1) (A) only (2) (C) only (3) (B) and (D) only (4) (D) only

Q40.The oxide that shows magnetic property is: (1) SiO2 (2) Mn3 O4 (3) Na2 O (4) MgO

Q40.Most suitable salt which can be used for efficient clotting of blood will be? (1) FeCl3 (2) Mg (HCO3)2 (3) FeSO4 (4) NaHCO3

Q40.The conditions given below are in the context of observing Tyndall effect in colloidal solutions: (A) The diameter of the colloidal particles is comparable to the wavelength of light used. (B) The diameter of the colloidal particles is much smaller than the wavelength of light used. (C) The diameter of the colloidal particles is much larger than the wavelength of light used. (D) The refractive indices of the dispersed phase and the dispersion medium are comparable. (E) The dispersed phase has a very different refractive index from the dispersion medium. Choose the most appropriate conditions from the options given below: (1) (A) and (E) only (2) (C) and (D) only (3) (A) and (D) only (4) (B) and (E) only

Q40.The parameters of the unit cell of a substance are a = 2. 5, b = 3. 0, c = 4. 0, α = 90°, β = 120°γ = 90°. The crystal system of the substance is : (1) Hexagonal (2) Orthorhombic (3) Monoclinic (4) Triclinic

Q40.Match List - I with List - II : List - I List - II (Unit) (Parameter) (a) Cell constant (i) S cm2 mol-1 (b) Molar conductivity (ii) Dimensionless (c) Conductivity (iii) m-1 (d) Degree of dissociation of electrolyte (iv) Ω-1 m-1 (1) (a)-(iii), (b)-(i), (c)-(iv), (d)-(ii) (2) (a)-(iii), (b)-(i), (c)-(ii), (d)-(iv) (3) (a)-(iii), (b)-(iv), (c)-(i), (d)-(ii) (4) (a)-(ii), (b)-(i), (c)-(iii), (d)-(iv)

Q40.Reducing smog is a mixture of: JEE Main 2021 (17 Mar Shift 1) JEE Main Previous Year Paper (1) Smoke, fog and O3 (2) Smoke, fog and SO2 (3) Smoke, fog and CH2 = CH −CHO (4) Smoke, fog and N2O3

Q40.The correct order of following 3d metal oxides, according to their oxidation numbers is : (a) CrO3 (b) Fe2O3 (c) MnO2 (d) V2O5 (e) Cu2O (1) ( d ) > ( a ) > ( b ) > ( c ) > ( e ) (2) ( a ) > ( c ) > ( d ) > ( b ) > ( e ) (3) ( a ) > ( d ) > ( c ) > ( b ) > ( e ) (4) ( c ) > ( a ) > ( d ) > ( e ) > ( b )

Q41.For the coagulation of a negative sol, the species below, that has the highest flocculating power is: (1) SO2−4 (2) Ba2+ (3) Na+ (4) PO3−4

Q41.The major components in "Gun Metal" are: (1) Cu, Sn and Zn (2) Al, Cu, Mg and Mn (3) Cu, Ni and Fe (4) Cu, Zn and Ni

Q41.Match List- I with List- II. List- I List- II (Ore) (Element Present) (a) Kernite (p) Tin (b) Cassiterite (q) Boron (c) Calamine (r) Fluorine (d) Cryolite (s) Zinc Choose the most appropriate answer from the options given below: (1) (a) →(r), (b) →(p), (c) →(q), (d) →(s) (2) (a) →(q), (b) →(s), (c) →(p), (d) →(r) (3) (a) →(p), (b) →(r), (c) →(s), (d) →(q) (4) (a) →(q), (b) →(p), (c) →(s), (d) →(r)

Q41.Isotope(s) of hydrogen which emits low energy β− particles with t1/2 value > 12 years is/are (1) Protium (2) Tritium (3) Deuterium (4) Deuterium and Tritium