Practice Questions

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

Q38.The gas released during anaerobic degradation of vegetation may lead to: (1) Corrosion of metals (2) Ozone hole (3) Global warming and cancer (4) Acid rain

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.Green chemistry in day-to-day life is in the use of: (1) Chlorine for bleaching of paper (2) Large amount of water alone for washing clothes (3) Tetrachloroethene for laundry (4) Liquified CO2 for dry cleaning of clothes

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.Tyndall effect is more effectively shown by: (1) lyophilic colloid (2) suspension (3) lyophobic colloid (4) true solution

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

Q39.Given below are two statements: Statement I: The pH of rain water is normally ~5. 6. Statement II : If the pH of rain water drops below 5. 6 , it is called acid rain. In the light of the above statements, choose the correct answer from the options given below: (1) Both Statement I and Statement II are true. (2) Statement I is false but Statement II is true. (3) Statement I is true but Statement II is false. (4) Both Statement I and Statement II are false.

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

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

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.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.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

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.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 )

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

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