Title CHEM ✅

DEMOZTRATE EDUCATION CENTRE FINAL EXAMINATION 2024 CHEMISTRY PAPER – XI Date: 05-05-2024 12:00pm to 12:20pm SECTION “A” (MULTIPLE CHOICE QUESTIONS) – (MCQs) Max Marks: 17 Time: 20 Minutes NOTE: i) This section consists of 17 part questions and all are to be answered. Each question carries one mark. ii) The correct answer bubble must be filled on OMR sheet 1)     passed in answer script. iii) Use only blue/black ball point pen or pointer on OMR sheet. iv) Avoid using pencil/White-o pen on OMR sheet. Q.1: Choose the best correct answer from the options given below. 1) Highest number of molecules present in the following sample of gas: (a) 100g O2 (b) 100g CH4 (c) 100g CO2 (d) 100g Cl2 2) Bohr theory is not applicable to: (a) H atom (b) H+ ion (c) He+ ion (d) Be+2 ion 3) This is not the property of colloidal solutions: (a) Tyndall effects (b) Brownian motion (c) Electrophoresis (d) Transparent appearance 4) In which of the following cases, the reaction nearly goes to completion: (a) Kc = 0.0025 (b) Kc = 450000 (c) Kc = 25 (d) Kc = 1 5) Linde’s method is famous for the: (a) Crystallization (b) Gas Liquefaction (c) Liquid distillation (d) Condensation 6) A colloidal solution which is made up of solid into gas is: (a) Fog (b) Smoke (c) jelly (d) Milk 7) Hydrogen bonding is not involved in: (a) Liquid HF (b) Liquid CH4 (c) Ice (d) Liquid NH3 8) For the reaction PCl5(g) ⇌ PCl3(g) + Cl2(g) (a) Kp = Kc (b) Kp > Kc (c) Kp < Kc (d) Kp = Ksp 9) This pair of gases has same rate of diffusion at STP: (a) N2 and O2 (b) C3H8 and CO2 (c) He and H2 (d) Cl2 and CH4 10) The sum of mole fraction of solute and solvent is equal to: (a) Zero (b) 1 (c) 10 (d) 100
11) All of the following process are categorized into exothermic reactions except: (a) Combustion (b) Neutralization (c) Oxidation (d) Decomposition 12) The intermediate phase lying between the solid and liquid phase is called: (a) Crystalline solid (b) Liquid Crystals (c) Crystal growth (d) Crystal lattice 13) At constant pressure, the heat of a system is represented by: (a) q = E (b) q = w (c) q = V (d) q = H 14) The decomposition of H2O2 is inhibited by: (a) Ethanol (b) Glycerin (c) MnO2 (d) V2O5 15) K + is isoelectronic with: (a) Cl–1 (b) F-1 (c) Na+1 (d) Mg+2 16) Which one is the example of buffer: (a) HCl/NaCl (b) NaOH/H2CO3 (c) NH4OH/NH4Cl (d) NaOH/NaCl 17) Quantum number values for 3s orbital are: (a) n = 0, l = 1 (b) n = 1, l = 0 (c) n = 3, l = 1 (d) n = 3, l = 0 - - - - - - - - - - - x x x x x x x x x x x - - - - - - - - - - -
DEMOZTRATE EDUCATION CENTRE FINAL EXAMINATION 2024 Date: 05-05-2024 12:20pm to 03:00pm CHEMISTRY PAPER – XI SECTION “B” (SHORT-ANSWER QUESTIONS) (36 Marks) Max Marks: 68 Time: 2 Hours 40 Mins. NOTE: Answer any Nine part questions. All part questions carry equal marks. Q.2 (i) Define the following: * Stoichiometry * Rounding off Data * Activation Energy * Dipole moment (ii) Aluminum carbide is a hard solid and used as abrasive in cutting tools. It is prepared by the reaction of carbon and aluminum at elevated temperature. 3C + 4Al Al4C3 If 216 g carbon and 540 g Aluminum are mixed together for the reaction, determine the mass of Al4C3 formed and also identify the Limiting reactant. (At. Mass of Al is 27) (iii) 500cm3 of CH4 effuses from a porous material in 40 seconds while 375cm3 of an unknown gas effuses from the same porous material in 60 seconds. Determine the molecular mass of unknown gas. (iv) State Hund’s rule and write down the electronic configuration of the following: * Mo (z = 42) * S-2 (z = 16) * Sr+2 (z = 38) (v) Give the origin, properties and uses of X-rays. (vi) Differentiate between any four of the following. * Polar bond & non polar bond * Principal & Azimuthal Quantum Number * Isomorphism & polymorphism * Ideal & non ideal solution * Order of reaction & molecularity (vii) Give reasons for any four the following. * Bond dissociation energy of HCl is higher than Cl2 * Evaporation causes cooling * Graphite is a conductor of electricity * Powder marble reacts more vigorously with HCl than the chunk of marble * Molecular solids possess low melting point (viii) Draw a molecular orbital diagram of O2 molecule and determine its bond order. (ix) What is the difference between primary and secondary battery? Draw a diagram of Dry cell and write the redox reaction taking place in it. (x) In the manufacturing of HNO3 by the Ostwald process, one of the most important exothermic reactions is the oxidation of ammonia. 4NH3(g) + 5O2(g) 4NO(g) + 6H2O(l) Determine standard heat of reaction (H) from the following given data. ∆Hf o of NH3(g) = - 46.19KJ/mol ∆Hf o of NO(g) = 90.25KJ/mol ∆Hf o of H2O(l) = - 285.8KJ/mol
(xi) Define acid and base in terms of * Lowry bronsted theory * Lewis theory (xii) State Le-Chatelier’s principle. Explain the industrial application of Le-Chatelier’s principle using Haber’s process. (xiii) Determine the molality of a 10% urea solution (CON2H4). OR Should AgCl precipitate from a solution prepared by mixing 400ml of 0.01M NaCl and 600ml of 0.03M AgNO3 (Ksp of AgCl = 1.8 x 10-10) (xiv) Define homogenous and heterogeneous catalysis with example of each. OR A certain reaction A + B  C gave the following data. Determine the order of reaction and the rate constant. Concentration (mole/dm3 ) Rate (mole/dm3 ) A B 0.1 0.1 3 x 10-3 0.2 0.1 12 x 10-3 0.1 0.3 9 x 10-3 SECTION “C” (DETAILED-ANSWER QUESTIONS) (32 MARKS) Note: Answer any Two questions from this section. All questions carry equal marks. Q. 3: (a) What is line spectrum? Describe Bohr’s explanation about various spectral lines of hydrogen spectrum and derive an expression for the frequency of radiation of hydrogen spectrum. Given: r = εo n 2h 2 πmze 2 K.E = Ze2 8πεor P.E = −Ze2 4πεor OR What is meant by Radioactivity? Give the properties of , β and  rays and write four uses of nuclear radiations. (b) State the law of mass action. Explain the use of Kc in predicting the extent of reaction. If Kc for the given reaction at 727C is 4.2 x 10–3 , calculate its Kp. CH4(g) + 2H2S(g) ⇌ CS2(g) + 4H2(g) Q. 4 (a) What is an Ideal gas? What are the causes of deviation of real gas from ideal behavior? If one mole of ammonia gas is kept in a cylinder of 5.5dm3 at 27C, assuming ammonia gas as a real gas, determine its pressure. The Van der Waal constants for ammonia gas are “a = 4.17 atm dm6 mol-2 and b = 0.0371 dm3 mol-1 .” (b) What is meant by Hybridization? Explain sp3 hybridization in CH4 and sp2 hybridization in C2H4 molecules. Q. 5 (a) What is meant by colligative properties? Explain the elevation of boiling point and derive the formula of molecular mass of solute by elevation in the boiling point. (b) Balance the following equation by ion electron method. * Cr(OH)3 + ClO3 −1 CrO4 −2 + Cl−1 (Basic medium) * MnO̅4 + NO̅2 Mn +2 + NO̅3 (Acidic medium) - - - - - - - x x x x x - - - - - - -