Practice Questions

Q39.Formation of photochemical smog involves the following reaction in which A, B and C are respectively. hu (i) NO2 ⟶A + B JEE Main 2023 (30 Jan Shift 1) JEE Main Previous Year Paper (ii) B + O2 →C (iii) A + C →NO2 + O2 Choose the correct answer from the options given below: (1) O, NO and NO3- (2) O, N2O and NO (3) N, O2 and O3 (4) NO, O and O3

Q40.Match List I with List II List I Industry List II Waste Generated (A) Steel plants (I) Gypsum (B) Thermal power plants (II) Fly ash (C) Fertilizer Industries (III) Slag (D) Paper mills (IV) Bio-degradable wastes Choose the correct answer from the options given below : (1) A - III, B - II, C - I, D - IV (2) A - III, B - IV, C - I, D - II (3) A - II, B - III, C - IV, D - I (4) A - IV, B - I, C - II, D - III

Q40.The correct order of hydration enthalpies is (A) K+ (B) Rb+ (C) Mg2+ JEE Main 2023 (29 Jan Shift 1) JEE Main Previous Year Paper (D) Cs+ (E) Ca2+ Choose the correct answer from the options given below: (1) C > A > E > B > D (2) E > C > A > B > D (3) C > E > A > D > B (4) C > E > A > B > D

Q40.The element playing significant role in neuromuscular function and interneuronal transmission is : (1) Be (2) Mg (3) Ca (4) Li

Q40.Ion having highest hydration enthalpy among the given alkaline earth metal ions is: (1) Be2+ (2) Sr2+ (3) Ba2+ (4) Ca2+

Q40. Mg (NO3)2. XH2 O and Ba (NO3)2. YH2 O, represent formula of the crystalline forms of nitrate salts. Sum of X and Y is.......

Q40.Match List I with List II LIST I – Enzymatic reaction LIST II - Enzyme A Sucrose→ Glucose and Fructose I Zymase B Glucose → ethyl alcohol and CO2 II Pepsin C Starch → Maltose III Invertase D Proteins → Amino acids IV Diastase Choose the correct answer from the options given below. (1) A - I, B - II, C - IV, D - III (2) A - III, B - I, C - IV, D - II (3) A - III, B - I, C - II, D - IV (4) A - I, B - IV, C - III, D - II

Q41.The delicate balance of CO2 and O2 is NOT disturbed by (1) Respiration (2) Burning of coal (3) Deforestation (4) Burning of petroleum

Q41.Which of the following can reduce decomposition of H2O2 on exposure to light (1) Urea (2) Alkali (3) Glass containers (4) Dust

Q41.In the extraction process of copper, the product obtained after carrying out the reactions (i) 2Cu2 S + 3O2 ⟶2Cu2O + 2SO2 (ii) 2Cu2O + Cu2 S ⟶6Cu + SO2 is called (1) Blister copper (2) Reduced copper (3) Copper scrap (4) Copper matte

Q41.Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R. Assertion A : The diameter of colloidal particles in solution should not be much smaller than wavelength of light to show Tyndall effect. Reason R : The light scatters in all directions when the size of particles is large enough. In the light of the above statements, choose the correct answer from the options given below : JEE Main 2023 (13 Apr Shift 2) JEE Main Previous Year Paper (1) Both A and R are correct but R is NOT the (2) A is true but R is false correct explanation of A (3) A is false but R is true (4) Both A and R are correct and R is the correct explanation of A

Q41.What is the purpose of adding gypsum to cement? (1) To facilitate the hydration of cement (2) To slow down the process of setting (3) To give a hard mass (4) To speed up the process of setting

Q41.The density of alkali metals is in the order (1) K < Cs < Na < Rb (2) Na < Rb < K < Cs (3) Na < K < Cs < Rb (4) K < Na < Rb < Cs

Q41.An ammoniacal metal salt solution gives a brilliant red precipitate on addition of dimethylglyoxime. The metal ion is : (1) 𝐶𝑢2 + (2) 𝑁𝑖2 + (3) 𝐹𝑒2 + (4) Co2 +

Q41.During the qualitative analysis of SO32 - using dilute H2SO4, SO2 gas is evolved which turns K2Cr2O7 solution (acidified with dilute H2SO4): (1) Black (2) Red (3) Green (4) Blue

Q41.Which of the following is used as a stabilizer during the concentration of sulphide ores? (1) Pine oils (2) Fatty acids (3) Xanthates (4) Cresols

Q41.A solution of FeCl3 when treated with K4Fe ( CN ) gives a prussian blue precipitate due to the formation of 6 (1) KFe2 ( CN ) (2) FeFe ( CN ) 6 6 (3) Fe3Fe ( CN ) (4) Fe4Fe ( CN ) 62 63

Q41.During the borax bead test with CuSO4 , a blue green colour of the bead was observed in oxidising flame due to the formation of (1) Cu3 B2 (2) Cu (3) Cu (BO2)2 (4) CuO

Q42.For a good quality cement, the ratio of lime to the total of the oxides of Si, Al and Fe should be as close as to (1) 4 (2) 1 (3) 2 (4) 3

Q42.The correct relationships between unit cell edge length ‘a’ and radius of sphere ‘r’ for face-centred and body- centred cubic structures respectively are: (1) 2√2r = a and √3r = 4a (2) r = 2√2a and 4r = √3a (3) r = 2√2a and √3r = 4a (4) 2√2r = a and 4r = √3a

Q42.The concentration of dissolved Oxygen in water for growth of fish should be more than X ppm and ¯ Biochemical Oxygen Demand in clean water should be less than Y ppm. X and Y in ppm are, respectively. ¯ (1) X Y (2) X Y 6 5 4 8 (3) X Y (4) X Y 4 15 6 12

Q42.Which one of the following is not an example of calcination? (1) CaCO3 Δ→CaO + CO2 (2) Fe2 O3. xH2 O Δ→Fe2 O3 + xH2 O (3) (4) 2PbS + 3O2 Δ→2PbO + 2 SO2 CaCO3. MgCO3 Δ→CaO + MgO + 2 CO2

Q42.The correct order of basicity of oxides of vanadium is JEE Main 2023 (31 Jan Shift 1) JEE Main Previous Year Paper (1) V2O3 > V2O4 > V2O5 (2) V2O3 > V2O5 > V2O4 (3) V2O5 > V2O4 > V2O3 (4) V2O4 > V2O3 > V2O5

Q43.Given below are two statements: One is labelled as Assertion A and the other is labelled as Reason R. Assertion A: can be easily reduced using Zn −Hg / HCl to Reason R: Zn −Hg / HCl is used to reduce carbonyl group to – CH2 – group. In the light of the above statements, choose the correct answer from the options given below: (1) A is false but R is true (2) A is true but R is false (3) Both A and R are true but R is not the correct (4) Both A and R are true and R is the correct explanation of A explanation of A

Q43.Nd2 + = ______ (1) 4f26s2 (2) 4f4 (3) 4f3 (4) 4f46s2