Practice Questions

Q37.How many electrons are involved in the following redox reaction ? Cr2O2−7 + Fe2+ + C2O2−4 →Cr3 + + Fe3+ + CO2 (Unbalanced) (1) 6 (2) 5 (3) 3 (4) 4

Q37.In allene (C3H4), the type(s) of hybridization of the carbon atoms is (are) : (1) sp and sp3 (2) sp2 and sp (3) only sp2 (4) sp2 and sp3

Q37.The temperature at which oxygen molecules have the same root mean square speed as helium atoms have at 300 K is : (Atomic masses : He = 4 u, O = 16 u) (1) 600 K (2) 2400 K (3) 1200 K (4) 300 K

Q38.In which of the following reactions H2O2 acts as a reducing agent ? (a) H2O2 + 2H+ + 2e−→2H2O (b) H2O2 −2e−→O2 + 2H+ (c) H2O2 + 2e−→2OH− (d) H2O2 + 2OH−−2e−→O2 + 2H2O (1) (a) , (b) (2) (c) , (d) (3) (a) , (c) (4) (b) , (d)

Q38.The (S∘) of the following substances are: CH4 g)186.2JK−1 mol−1 O2 (g) 205.2JK−1 mol−1 CO2( g)213.6JK−1 mol−1 H2O(g) 69.9.JK −1 mol−1 The entropy change (ΔS∘) for the reaction CH4( g) + 2O2( g) →CO2( g) + 2H2O (l) is: (1) −312.5 J K−1 mol−1 (2) −242.8JK−1 mol−1 (3) −108.1JK−1 mol−1 (4) −37.6 J K−1 mol−1

Q38.Van der Waal's equation for a gas is stated as, nRT n 2 P = V−nb −a( V ) . JEE Main 2014 (09 Apr Online) JEE Main Previous Year Paper This equation reduces to the perfect gas equation, P = nRTV When, (1) temperature is sufficiently high and pressure is (2) both temperature and pressure are very low. low. (3) both temperature and pressure are very high. (4) temperature is sufficiently low and pressure is high.

Q39.Amongst LiCl, RbCl, BeCl2 and MgCl2 the compounds with the greatest and the least ionic character, respectively are : (1) MgCl2 and BeCl2 (2) RbCl and MgCl2 (3) LiCl and RbCl (4) RbCl and BeCl2

Q39.For the estimation of nitrogen, 1. 4 g of an organic compound was digested by the Kjeldahl method and the evolved ammonia was absorbed in 60 ml of 10M sulphuric acid. The unreacted acid required 20 ml of 10M sodium hydroxide for complete neutralization. The percentage of nitrogen in the compound is (1) 6% (2) 10% (3) 3% (4) 5%

Q39.The molar heat capacity (Cp) of CD2O is 10 cals at 1000 K. The change in entropy associated with cooling of 32 g of CD2O vapour from 1000 K to 100 K at constant pressure will be: (D = deuterium, atomic mass = 2u) (1) 23.03caldeg−1 (2) −23.03caldeg−1 (3) 2.303caldeg−1 (4) −2.303caldeg−1

Q39.The standard enthalpy of formation of NH3 is − 46. 0 kJ / mol. If bond enthalpy of H2 is −436 kJ / mol and that of N2 is −712 kJ / mol , the average bond enthalpy of N −H bond in NH3 is : (1) − 964 kJ / mol (2) − 1102 kJ / mol (3) + 1056 kJ / mol (4) + 352 kJ / mol

Q40.At a certain temperature, only 50% HI is dissociated into H2 and I2 at equilibrium. The equilibrium constant is : (1) 0.5 (2) 4.0 (3) 1.0 (4) 0.25

Q40.Considering the basic strength of amines in an aqueous solution, which one has the smallest pKb value? (1) (CH3) NH (2) CH3 NH2 (3) (CH3)3N (4) C6H5 NH2

Q40.Consider the following equilibrium AgCl ↓+2NH3 ⇌[Ag(NH322]+ + Cl− White precipitate of AgCl appears on adding which of the following? JEE Main 2014 (11 Apr Online) JEE Main Previous Year Paper (1) NH3 (2) aqueous NaCl (3) aqueous HNO3 (4) aqueous NH4Cl

Q41.The major organic compound formed by the reaction of 1, 1, 1 - trichloroethane with silver powder is : (1) Acetylene (2) Ethene (3) 2 - Butyne (4) 2 - Butene

Q41.Which of these statements is not true ? (1) LiAlH4 is versatile reducing agent in organic (2) NO+ is isoelectronic with O2 synthesis. (3) Boron is always covalent in its compounds (4) In aqueous solution, the Tl+ ion is much more stable than Tl (III) JEE Main 2014 (19 Apr Online) JEE Main Previous Year Paper

Q41.Assuming that the degree of hydrolysis is small, the pH of 0.1M solution of sodium acetate (Ka = 1.0 × 10−5) will be: (1) 5.0 (2) 6.0 (3) 8.0 (4) 9.0

Q41.In which of the following pairs A is more stable than B? (1) (2) (3) (4)

Q42.Hydrogen peroxide acts both as an oxidising and as a reducing agent depending upon the nature of the reacting species. In which of the following cases H2O2 acts as a reducing agent in acid medium? (1) MnO−4 (2) Cr2O2−7 (3) SO2−3 (4) KI

Q42. CsCl crystallises in body centred cubic lattice. If 'a' is its edge length then which of the following expressions is correct? (1) rCs+ + rCl−= 3a (2) rCs+ + rCl−= 3a2 (3) rCs+ + rCl−= √32 a (4) rCs+ + rCl−= √3a

Q42.Which of the following statements about Na2O2 is not correct? (1) It is diamagnetic in nature (2) It is derivative of H2O2 (3) Na2O2 oxidises Cr3+ to CrO2−4 in acid medium. (4) It is the super oxide of sodium

Q42.In a face centered cubic lattice atoms A are at the corner points and atoms B at the face centered points. If atom B is missing from one of the face centered points, the formula of the ionic compound is : (1) A2B3 (2) AB2 (3) A5B2 (4) A2B5

Q43.Which one of the following acids does not exhibit optical isomerism? (1) Lactic acid (2) Tartaric acid (3) Maleic acid (4) α-amino acids

Q43.Consider separate solutions of 0. 500 M C2H5 OH (aq), 0. 100 M Mg3 (PO4)2 (aq), 0. 250 M KBr (aq) and 0. 125 M Na3 PO4 (aq) at 25°C. Which statement is true about these solutions, assuming all salts to be JEE Main 2014 (06 Apr) JEE Main Previous Year Paper strong electrolytes? (1) They all have the same osmotic pressure. (2) 0. 100 M Mg3(PO4)2 (aq) has the highest osmotic pressure. (3) 0. 125 M Na3 PO4 (aq) has the highest osmotic (4) 0. 500 M C2H5 OH (aq) has the highest osmotic pressure. pressure.

Q43.A current of 10. 0 A flows for 2. 00 h through an electrolytic cell containing a molten salt of metal X . This results in the decomposition of 0. 250 mol of metal X at the cathode. The oxidation state of X in the molten salt is: (F = 96, 500 C) (1) 1+ (2) 4+ (3) 3+ (4) 2+ JEE Main 2014 (09 Apr Online) JEE Main Previous Year Paper A, B, C and D are −1.2 V,0.6 V, 0.85 V and

Q43. The reagent needed for converting (1) Cat. Hydrogenation (2) H2 /Lindlar Cat. (3) Li/NH3 (4) LiAlH4