Supportive Seminars for G.C.E.(A/L) Revision Paper Chemistry

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1 Prepared by : Ministry of Education Supportive Seminars for G.C.E.(A/L) Revision Paper Chemistry Part I - Time :Two hours 50 multiple choice questions with 5 options, and all questions should be answered. As 2 marks for the correct answer to each question, total marks are 100. Part II - Time : Three hours This question paper consists of two parts - structured and essay. Part A - Answer all four structured questions. As 100 marks for each question, total marks are 400. Part B - Answer two questions. As 150 marks for each question, total marks are 00. Part C - Answer two questions. As 150 marks for each question, total marks are 00. Part II - Total marks = 100 Calculating the final marks Part I = 100 Part II = 100 Total =200 2 = 100 PART - I Answer all questions choose the correct or the most appropriate answer Universal gas constant R = 8.14 JK -1 mol -1 Avogadro constant N A = x 10 2 mol The number of protons, neutrons and electrons in the ion 50 Sn 2+ respectively are, 1) 50, 69, 48 2) 50, 69, 50 ) 119, 50, 69 4) 69, 50, 69 5) 50, 119, During the reaction BH + NH H B - _ NH the HBH bond angle, 1) changes from to ) changes from 90 0 to ) changes from to ) remains 90 0 in both the reactant and the product 5) remains in both the reactant and the product. Which of the following compounds contains the highest number of unpaired electrons? + 1) TiCl 2) MnCl 2 ) FeS 4 4) CuS 4 5) FeCl 1

2 4. The rate constant k of the reaction, A(g) +2B(g) C(g) is 0.25 mol -1 dm s -1. The acceptable rate equation(s) for this reaction is/are, (a) R = k[a(g)][b(g)] (b) R = k [B(g)] 2 (c) R = k [A(g)][B(g)] 2 1) a only 2) b only ) c only 4) a and b only 5) b and c only 5. At temperature T, the dissociation constant of a weak monoacid base is 2 x 10-6 mol dm -. What is the ph of a 0.5 mol dm - aqueous solution of this base? (K w of water at T is 1 x mol 2 dm -6 ) 1) ) ) 11 4) ) 1 6. In which aqueous solution(s) of the following compound(s), the ph will not change considerably on addition of a small amount of a dilute acid? (a) (b) NH (c) NH 4 Cl (d ) CH CK CH CK 1) a only 2) a and d only ) a, b and d only 4) b, c and d only 5) a, b and c only 7. A compound formed in the process of production of urea is 1) NH 2 CNH 4 2) (NH 4 ) 2 C ) CaC 4) Ca(H) 2 5) NH 4 H 8. The first five successive ionization energies of the element X (in kj mol -1 ) are 801, 2427, 660, 25025, Which of the following can be the formula of the oxide of X? 1) X 2) X 2 ) X 2 4) X 2 5) X When excess dilute hydrochloric acid is added to a [Cu(NH ) 4 ]S 4 solution, 1) ammonia gas is liberated. 2) a blue - green solution is formed. ) a yellow solution is formed. 4) a white precipitate is formed. 5) no visible change is made in the solution. 2

3 10. Which of the following does not react with the compound 1) Mg 2) CH MgBr ) HCl 4) C 6 H 5 Cl 5) PCl 5 CH CH C H? H NH Which of the following statements is true about the molecule CH = CH C C H? 1) It decolorizes H - /KMn 4. 2) It gives a precipitate with ammonical silver nitrate. ) It is reduced by Ni/H 2. 4) Its all carbon atoms lie on the same plane. 5) The energy of all the C H bonds of it are equal. 12. Which of the following correctly indicates the descending order of basicity of the species given? ^1& CH >NH 2 > H C C - >H - ^2& H C C > CH > NH 2 > H - ^& H - > NH 2 > H C C - > CH CH ^4& NH 2 > H C C - > H - - > CH ^5& H - > H C C > NH 2 > CH 1. How many will be the total number of isomers formed if one hydrogen atom in the molecule CH CH CH is replaced by a Cl atom? 1) 2) 4 ) 5 4) 6 5) 7 CH 14. Which pair contains the carbon atoms of the same hybridization state? 1), C 2 H 4 2) CH 4, C 2 ) C 2 H 4, CH 4 4) C 2 H 6, 5), C 2 H 2

4 15. What can be Y in the following reaction scheme? conc.hn C 6 H 5 NHCCH H X + /H 2 Y conc. H 2 S 4 NH 2 + NH N 2 NH 2 + NH N 2 N 2 N2 N NHCCH 2 1) 2) ) 4) 5) 16. The IUPAC name of the compound CH = H C C C CH is CH 1) Methyl 4 - ethyl methyl oxopentanoate 2) Methyl 4 - ethyl oxohexanoate ) Methyl 4 - ethyl formyl hexenoate 4) Methyl 4 - ethyl oxomethylbutanote 5) Methyl 4 - ethyl oxo hexenoate 17. Which of the following would be obtained by the disproportionation of HCl? 1) Cl 2, HCI 2) HCI 2, HCI 4 ) HCl, Cl 2 4) HCl, HCl 5) HCl 2, HCl 18. According to Bronsted - Lowery theory which one cannot behave as a base? 1) H 2 2) NH ^& CH CH 4) H 2 S 4 5) HN 19. Mixed in a closed vessel are equal masses of methane and oxygen at temperature 298 K. What fraction of the total pressure is the partial pressure of oxygen? (C = 12, H = 1, = 16) 1) 1 /2 2) 2 / ) 1 /5 4) 1 / 5) /5 4

5 20. Which of the following is not true about nylon? 1) A type of nylon can be made from H 2 N C H 2) A type of nylon can be made from C = N-H ) The nylon chains are bonded to one another by hydrogen bonds 4) Nylon is thermo stable polymer. 5) Nylon can be produced from naphtha which is a by - product of petroleum industry 21. Which of the following contains all the species present in the solution formed when carbon dioxide gas dissolves in water? 1) C 2 (aq), H C (aq), HC (aq), C 2- (aq), H- (aq), H + (aq) 2 2) H 2 C (aq), C2- (aq), HC (aq), C 2 (aq) ) C 2- (aq), H 2 C (aq), H - (aq), H + (aq) 4) C C 2 (aq), H - 2- (aq) (aq), HC - (aq), 5) C 2 (aq), H C (aq), H +(aq) 2 HC - (aq), (a) PH (b) H 2 CCl 2 (c) AlCl What is the true statement of the following about A, B and C? 1) (a) and (b) are polar while (c) is non polar. 2) (a) is polar while (b) and (c) are non polar. ) (a), (b), and (c) are polar molecules. 4) (a), (b) and (c) are non polar molecules. 5) (a) and (c) are polar while (b) is non polar. 2. The white crystalline compound A on the addition of dilute H 2 S 4 liberates a brown coloured gas. When A is heated with aluminum powder and sodium hydroxide smell of ammonia can be detected. A can be 1) Al(N 2 ) 2) KN ) NaBr 4) Zn(N ) 2 5) Ca(N 2 ) 2 5

6 24. The activation energies of the forward and backward reaction of the reversible reaction A(g) B(g) are +25 kj mol -1 and +80 kj mol -1 respectively. The enthalpy of reaction of the above reaction ( in kj mol -1 ) is, 1) +55 2) -80 ) -55 4) +80 5) The natural rubber is 1) Cis - 1, 4 - polyisoprene 2) Trans - 1, 4 - polyisoprene ) Polychloroprene 4) Polybutadiene 5) Polyneoprene 26. At 25 0 C 0.0 cm of a 0.2 mol dm - solution of a monobasic weak acid were mixed with 10.0 cm of a 0.2 mol dm - NaH solution and the ph of the solution was found to be 5.0. What can be the dissociation constant K a of the weak acid at 25 0 C? 1) 2.5 x 10-4 mol dm - 2) 2.5 x 10-5 mol dm - ) 5 x 10-5 mol dm - 4). x 10-6 mol dm - 5) 5 x 10-6 mol dm Which of the following is not closely connected with the manufacture of acetylene? 1) Limestone 2) Coke ) Electricity 4) Water 5) Hydrogen 28) Which of the following can occur when an acidic KMn 4 solution is added to a KI solution? 1) The solution decolourize. 2) The solution becomes brown. ) The solution turns dark green. 4) Violet fumes of I 2 are liberated. 5) Black Mn 2 solid is formed. 6

7 29. f the following minerals, which is not used to produce iron. 1) iron pyrites 2) siderite ) ilmanite 4) haematite 5) limonite 0. In acid medium, Sn 2+ ions are oxidized by a solution of K 2 Cr 2 7. What amount of K 2 Cr 2 7 is required to oxidize 1 mol of Sn 2+ ions? 1) 1 / 2) 1 /6 ) 6 4) 5) 1 /2 Instructions for questions No For each of the questions 1 to 40, four responses (a), (b), (c) and (d) are given; out of which,one or more is/are correct. Select the correct response/responses. In accordance with the instructions given on your answer sheet, mark (1) if only (a) and (b) are correct. (2) if only (b) and (c) are correct. () if only (c) and (d) are correct. (4) if only (d) and (a) are correct. (5) if any other number or combination of responses is correct. (1) (2) () (4) (5) only (a) and (b) only (b) and (c) only (c) and (d) only (d) and (a) any other number or are correct are correct are correct are correct combination of responses is correct 1. Phenol reacts with (a) HN (b) CH CCl (c) CH CH (d) PCl 2. In which of the following the given enthalpy change is correctly described? Enthalpy change Relevant reaction (a) Standard enthalpy of sublimation of iodine I 2 (s) 2I(g) (b) Standard enthalpy of combustion of CH H(l) 2CH H(1) + 2 (g) 2C 2 (g) + 6H 2 (1) (c) Standard lattice enthalpy of MgBr 2 (s) Mg 2+ (g) + 2Br - (g) MgBr 2 (s) (d) Enthalpy of atomization of 2 (g) 2 (g) 2(g) 7

8 = = C H. Which of the following is /are true about the compound given? C Cl (a) It liberates C 2 with Na 2 C. (b) It gives a white precipitate with AgN solution. (c) It liberates C 2 with 2, 4 - DNP. (d) It does not decolourize acidified KMn The following equilibrium exists in a closed rigid container at 400 K. S 2 Cl 2 (g) S 2 (g) + Cl 2 (g) At 400 K, 0.50 mol of He gas were added to this hard container. The change/changes that would occur in the container is/are, (a) decrease of the mole fraction of S 2 (g) (b) increase of the total pressure of the system (c) increase of K c of the system (d) increase of the partial pressure of S 2 (g) 5. Which of the following statements is /are true about the elements of the group 2 of the periodic table? (a) (b) (c) (d) All the elements form basic oxides. Descending the group, the melting point of the elements increases. All form ionic compounds. Down the group, the thermal stability of the carbonates increases. 6. The change/changes that can be expected when a CuCl 2 solution is electrolyzed using copper electrodes is/are (a) (b) (c) (d) dissolution of the anode reduction at the negative pole liberation of hydrogen at the cathode blue color of the solution decreases 8

9 7. Which of the following statements is/are true about the molecule XeF 4? (a) Its shape is triangular bipyramidal. (b) Five atoms of the molecule lie on the same plane. (c) Two lone pairs of electrons are located on the Xe atom. (d) The angle FXeF is approximately Which of the following statements is/are false about an ideal gas? (a) (b) (c) (d) The root mean square speed of the gas increases with the increase of the relative molecular mass of the gas. The intermolecular distances are negligibly small. The average kinetic energy of the gas is directly proportional to the absolute temperature. The average kinetic energy of the gas increases with increase of its pressure. 9. In which of the following change/changes the sign of H, S and G is correctly designated? Reaction H S G ^a) Na + (g) + Cl - (g) NaCI(s) (-) (-) (+) (b& H 2 (s) H 2 (l) (+) (+) (-) (c& CaC (s) Ca(s) + C 2 (g) (+) (+) (+) (d& NaCl(s) Na + (aq) + Cl - (aq) (+) (-) (-) 40. A(s) + 2B(g) C(g) + D(g); H <0 In the above system at dynamic equilibrium which of the following cannot be used to obtain a maximum yield of C? (a) (b) (c) (d) increasing pressure addition of finely powdered A to the system addition of a catalyst decreasing temperature Instructions for questions No In question No 41 to 50 two statements are given in respect ot each question. From the table given below, select the response out of the responses (1), (2), (), (4) and (5) the best fits the two statements given for each of the questions and mark appropriately on your answer sheet. Response First statement Second statement (1) True True and correctly explains the first statement (2) True True but does not explain the first statement correctly () True False (4) False True (5) False False 9

10 First Statement Second Statement 41 Under the condition of low pressures vander Waals equation cannot be applied for real gases. 42 The lowering of the H + ion concentration caused by the dilution of a 2.0 mol dm - HCl solution to 0.2 mol dm - and 5.0 mol dm - HCl solution to 0.5 mol dm - is the same. 4 N 2 can be prepared by heating a mixture of NH 4 Cl and KN Under high pressures real gases approach ideal behavior. The ph value changes in one unit when an acid solution is diluted ten times. NH 4 Cl oxidizes KN to N 2 44 The compound C C Cl H Alkyl halides as well as aryl halides form Grignard's reagent. forms the corresponding Grignard's reagent in the presence of Mg and dry ether. 45. NaN cannot be used as a starting material to distinguish NaN react with dilute HCl. NH 2 NH 2 and 46. Four quantum numbers are essential to describe an electron in an aton. 47. NH 4 Cl can be used in the salt bridge of electrochemical cells Electrons display both wave and particle behaviour. + In NH 4 Cl, conductivities of NH 4 and Cl - ions are equal. 48. The half - life of a first order reaction is a constant. In a first order reaction, the rate changes linearly with the concentration. 49. AgCl cannot be prepared by reacting metallic silver with conc. HCl. HCl is not a powerful oxidizing acid. 50. All salts speed up the corrosion of iron. Ionization of salts increases the electrical conductivity of water. 10