Practice Questions

Q38.Addition of sodium hydroxide solution to a weak acid (HA) results in a buffer of pH 6. If ionization constant of HA is 10−5 , the ratio of salt to acid concentration in the buffer solution will be: (1) 10 : 1 (2) 4 : 5 (3) 5 : 4 (4) 1 : 10

Q39.A gas undergoes change from state A to state B. In this process, the heat absorbed and work done by the gas is 5 J and 8 J, respectively. Now gas is brought back to A by another process during which 3 J of heat is evolved. In this reverse process of B to A. (1) 6 J of the work will be done by the gas (2) 6 J of the work will be done by the surroundings on gas (3) 10 J of the work will be done by the surroundings (4) 10 J of the work will be done by the gas on gas

Q39.Both lithium and magnesium display several similar properties due to the diagonal relationship; however, the one which is incorrect is: (1) Both form soluble bicarbonates (2) Both form nitrides (3) Nitrates of both Li and Mg yield NO2 and O2 on (4) Both form basic carbonate heating

Q39.The pair of compounds having metals in their highest oxidation state is (1) Mn2 O7 and CrO2 Cl2. (2) [Fe (CN)6]3− and [Cu (CN)4]2−. (3) [NiCl4]2− and [CoCl4]2−. (4) [FeCl4]− and Co2 O3.

Q40.Which of the following molecules is least resonance stabilized? JEE Main 2017 (02 Apr) JEE Main Previous Year Paper (1) (2) (3) (4)

Q40.In which of the following reactions, hydrogen peroxide acts as an oxidizing agent? (1) HOCl + H2O2 →H3O+ + Cl−+ O2 (2) I2 + H2O2 + 2OH−→2I−+ 2H2O + O2 (3) PbS + 4H2O2 →PbSO4 + 4H2O (4) 2MnO−4 + 3H2O2 →2MnO2 + 3O2 + 2H2O + 2OH−

Q40.The following reaction occurs in the Blast Furnace where iron ore is reduced to iron metal: Fe2O3(s) + 3CO(g) ⇌2Fe (l) + 3CO2(g) Using the Le Chatelier's principle, predict which one of the following will not disturb the equilibrium? (1) Addition of CO2 (2) Removal of CO2 (3) Addition of Fe2O3 (4) Removal of CO Q41. 50 mL of 0 .2 M ammonia solution is treated with 25 mL of 0. 2 M HCl. If pKb of ammonia solution is 4. 75, the pH of the mixture will be: (1) 8. 25 (2) 9. 25 (3) 3. 75 (4) 4. 75

Q41.Which of the following compounds will form significant amount of meta product during mono-nitration reaction? (1) (2) (3) (4)

Q41.A metal M reacts with nitrogen gas to afford M3N, M3N on heating at high temperature gives back M and on reaction with water produces a gas B. Gas B reacts with an aqueous solution of CuSO4 to form a deep blue compound. M and B respectively are JEE Main 2017 (08 Apr Online) JEE Main Previous Year Paper (1) Li and NH3 . (2) Ba and NH3. (3) Na and N2. (4) Al and N2.

Q42.A water sample has ppm level concentration of following anions F- = 10; SO42 - = 100; NO3- = 50 The anion/anions that make/makes the water sample unsuitable for drinking is/are (1) Both SO42 - and NO3- (2) Only F- (3) Only SO42 - (4) Only NO3-

Q42.Consider the following ionization enthalpies of two elements 'A' and 'B'. Element Ionization enthalphy (kJ / mol) 1st 2nd 3rd A 899 1757 14847 B 737 1450 7731 Which of the following statements is correct? (1) Both 'A' and 'B' belong to group-1 where 'A' (2) Both 'A' and 'B' belong to group-2 where 'A' comes below 'B'. comes below 'B'. (3) Both 'A' and 'B' belong to group-1 where 'B' (4) Both 'A' and 'B' belong to group-2 where 'B' comes below 'A'. comes below 'A'.

Q42.Which one of the following is an oxide? (1) SiO2 (2) KO2 (3) BaO2 (4) CsO2

Q43.Which of the following statements is not true about partition chromatography? (1) Stationary phase is a finely divided solid (2) Separation depends upon equilibration of solute adsorbent. between a mobile and a stationary phase. (3) Mobile phase can be a gas. (4) Paper chromatography is an example of partition chromatography.

Q43.A metal crystallizes in a face centred cubic structure. If the edge length of its unit cell is 'a', the closest approach between two atoms in the metallic crystal will be (1) 2√2a (2) √2a a (3) (4) 2a √2

Q43.Which of the following compounds is most reactive to an aqueous solution of sodium carbonate? JEE Main 2017 (09 Apr Online) JEE Main Previous Year Paper (1) (2) (3) (4)

Q44.In the following structure, the double bonds are marked as I, II, III and IV. Geometrical isomerism is not possible at the site(s): (1) I and III (2) III (3) I (4) III and IV

Q44.The freezing point of benzene decreases by 0.45°C on adding 0 . 2 g of acetic acid to 20 g of benzene. If acetic acid associates to form a dimer in benzene, then what is the percentage association of acetic acid in benzene? Kf for benzene = 5 .12 K kg mol-1 (1) 80 . 4% (2) 74 . 6% (3) 94 . 6% (4) 64 . 6%

Q44.The IUPAC name of the following compound is: (1) 2−Ethyl −1, 1−dimethyl cyclohexane (2) 1, 1−Dimethyl −2−ethyl cyclohexane (3) 2, 2−Dimethyl −1 −1−ethyl cyclohexane (4) 1−Ethyl −2, 2−dimethyl cyclohexane

Q45.The major product of the following reaction is: (1) (2) (3) (4)

Q45.Which of the following compounds will not undergo Friedel Crafts reaction with benzene? (1) (2) (3) (4)

Q45.Given = - 0 .74 V ECl2o / Cl- = 1 .36 V, ECr3o + / Cr o ECr2O72 - / Cr3 + = 1 .33 V, EMnO4o - / Mn2 + = 1 .51 V . Among the following, the strongest reducing agent is: JEE Main 2017 (02 Apr) JEE Main Previous Year Paper (1) Mn2 + (2) Cr3 + (3) Cl- (4) Cr

Q46.Which of the following is a set of greenhouse gases? (1) O3, NO2, S O2, Cl2 (2) CH4, O3, N2, SO2 (3) CO2, CH4, N2O, O3 (4) O3, N2, CO2, NO2

Q46.Identify the pollutant gases largely responsible for the discoloured and lustreless nature of marble of the Taj Mahal. (1) SO2 and O3 (2) O3 and CO2 (3) SO2 and NO2 (4) CO2 and NO2 JEE Main 2017 (08 Apr Online) JEE Main Previous Year Paper Q47. 5g of Na2 SO4 was dissolved in x g of H2O . The change in freezing point was found to be 3 .82o C . If Na2 SO4 is 81. 5% ionised, the value of x ( Kf for water = 1 .86o C kg mol−1 ) is approximately: (molar mass of S = 32 g mol−1 and that of Na = 23 g mol−1 ) (1) 25 g (2) 65 g (3) 15 g (4) 45 g

Q46.Two reactions A1 and A2 have identical pre-exponential factors. The activation energy of A1 is more than A2 by 10 kJ mol-1 . If k1 and k2 are the rate constants for reactions A1 and A2, respectively at 300 K, then k2 ln⁡ is equal to k1 R = 8 .314 J mol-1K-1 (1) 12 (2) 6 (3) 4 (4) 8

Q47.The Tyndall effect is observed only when the following conditions are satisfied, i The diameter of the dispersed particles is much smaller than the wavelength of the light used. ii The diameter of the dispersed particle is not much smaller than the wavelength of the light used. iii The refractive indices of the dispersed phase and dispersion medium are almost similar in magnitude. iv The refractive indices of the dispersed phase and dispersion medium differ greatly in magnitude. (1) ii and iv (2) i and iii (3) ii and iii (4) i and iv