Years IIT-JEE CHAPTERWISE SOLVED PAPERS CHEMISTRY Information contained in this work has been obtained by Career Point from sources believed to be reliable. However, neither Career Point nor its authors guarantee the accuracy or completeness of any information published herein, and neither Career Point nor its authors shall be responsible for any errors, omissions, or damages arising out of use of this information. This work is published with the understanding that Career Point and its authors are supplying information but are not attempting to render any professional services. If such services are required, the assistance of an appropriate professional should be sought. CAREER POINT CP Tower, Road No.-1, IPIA, Kota (Raj.) Email : [email protected] Copyright © 2016, by Career Point Ltd. No part of this publication may be reproduced or distributed in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise or stored in a database or retrieval system without the prior written permission of the Publishers. The program listings (if any) may be entered, stored and executed in a computer system, but they may not be reproduced for publication. This edition can be exported from India only by the publisher. Published by Career Point Ltd. CP Tower, Road No.-1, IPIA, Kota (Raj.) Email : [email protected] Preface Whenever a student decides to prepare for any examination, her/his first and foremost curiosity about the type of questions that he/she has to face. This becomes more important in the context of competitive examinations where there is neck-to-neck race. We feel great pleasure to present before you this book. We have made an attempt to provide chapter wise questions asked in IIT-JEE / JEE Advanced from 1978 to 2016 along with solutions. Solutions to the questions are not just sketch rather have been written in such a manner that the students will be able to under the application of concept and can answer some other related questions too. We firmly believe that the book in this form will definitely help a genuine, hardworking student. We have tried our best to keep errors out of this book. Comment and criticism from readers will be highly appreciated and incorporated in the subsequent edition. We wish to utilize the opportunity to place on record our special thanks to all team members of Content Development for their efforts to make this wonderful book. Career Point Ltd. CONTENTS Chapter Page No. 1. Mole‐Concept & Stoichiometry ♦ Answers ♦ Solutions 1‐30 10 11 2. Atomic Structure ♦ Answers ♦ Solutions 31‐46 38 39 3. Chemical Bonding ♦ Answers ♦ Solutions 47‐66 54 55 4. Gaseous & Liquid States ♦ Answers ♦ Solutions 67‐90 77 78 5 Chemical & Ionic Equilibrium ♦ Answers ♦ Solutions 6. Chemical Energetics ♦ Answers ♦ Solutions 121‐140 130 131 7. Periodic Table ♦ Answers ♦ Solutions 141‐148 144 145 8. Extraction of Metals & the s‐block elements ♦ Answers ♦ Solutions 149‐160 154 155 9. General organic Chemistry ♦ Answers ♦ Solutions 161‐186 10. Hydrocarbons & Halogen Derivatives ♦ Answers ♦ Solutions 187‐218 200 202 11. Colligative Properties of solutions ♦ Answers ♦ Solutions 219‐232 224 225 91‐120 101 102 173 174 Cont.... 12. Chemical Kinetic & Nuclear Chemistry ♦ Answers ♦ Solutions 233‐254 242 243 13 Solid State, Surface Chemistry & Colloids ♦ Answers ♦ Solutions 255‐266 261 262 14. Electrochemistry ♦ Answers ♦ Solutions 267‐292 277 278 15. The p‐block elements ♦ Answers ♦ Solutions 293‐322 306 308 16. The transition & Co‐ordination compounds ♦ Answers ♦ Solutions 323‐350 335 337 17. Analytical chemistry ♦ Answers ♦ Solutions 351‐364 357 358 18. Compounds containing oxygen ♦ Answers ♦ Solutions 365‐434 19. 20. 21. Compounds containing nitrogen & Practical organic chemistry ♦ Answers ♦ Solutions Carbohydrates Aminoacids & Misc Match the following ♦ Answers ♦ Solutions Model Test Papers ♦ Practice Test‐1 [Paper‐1] ♦ Practice Test‐1 [Paper‐2] ♦ Practice Test‐2 [Paper‐1] ♦ Practice Test‐2 [Paper‐2] 391 393 435‐466 446 447 467‐476 473 474 477‐500 477 483 489 495 Chapter 1 Mole Concept & Stoichiometry ONLY ONE CORRECT ANSWER 1. 27 g of Al will react completely with how many grams of oxygen ? [1978] (A) 8 g (B) 16 g (C) 32 g (D) 24 g 2. A compound was found to contain nitrogen and oxygen in the ratio 28 gm and 80 gm respectively. The formula of compound is [1978] (A) NO (B) N2O3 (D) N2O4 (C) N2O5 3. The largest number of molecules is in (A) 36 g of water (B) 28 g of carbon monoxide (C) 46 g of ethyl alcohol (D) 54 g of nitrogen pentaoxide 4. 5. 6. 7. 8. If 0.50 mole of BaCl2 is mixed with 0.20 mol of Na3PO4, the maximum number of moles of Ba3(PO4)2 that can be formed is [1981, 1M] (A) 0.70 (B) 0.50 (C) 0.20 (D) 0.10 9. One mole of N2H4 loses ten moles of electrons to form a new compound Y. Assuming that all the nitrogen appears in the new compound, what is the oxidation state of nitrogen in Y ? (There is no change in the oxidation state of hydrogen). [1981, 1M] (A) –1 (B) –3 (C) +3 (D) +5 10. The oxidation number of carbon in CH2O is [1982, 1M] (A) –2 (B) +2 (C) 0 (D) +4 11. A molal solution is one that contains one mole of a solute in [1986, 1M] (A) 1000 g of the solvent (B) one litre of the solvent (C) one litre of the solution (D) 22.4 litres of the solution 12. The brown ring complex compound is formulated as [Fe(H2O)5(NO)+]SO4. The oxidation state of iron is : [1987, 1M] (A) 1 (B) 2 (C) 3 (D) 0 13. The equivalent weight of MnSO4 is half its molecular weight when it is converted to : [1988, 1M] (A) Mn2O3 (B) MnO2 [1979] The total number of electrons in one molecule of carbon dioxide is [1979] (A) 22 (B) 44 (C) 66 (D) 88 A gaseous mixture contains oxygen and nitrogen in the ratio of 1 : 4 by weight. Therefore the ratio of their number of molecules is [1979] (A) 1 : 4 (B) 1 : 8 (C) 7 : 32 (D) 3 : 16 2.76 g of silver carbonate on being strongly heated yields a residue weighing [1979] (A) 2.16 g (B) 2.48 g (C) 2.32 g (D) 2.64 g M is molecular weight of KMnO4. The equivalent weight of KMnO4 when it is converted into K2MnO4 is [1980] (A) M (B) M/3 (C) M/5 (D) M/7 (C) MnO −4 (D) MnO 24− 2 39 YEARS TOPIC- WISE JEE Advanced Questions with Solutions 14. In which mode of expression, the concentration of a solution remains independent of temperature ? [1988, 1M] (A) Molarity (B) Normality (C) Formality (D) Molality 15. The oxidation number of phosphorus in Ba(H2PO2)2 is : [1990, 1M] (A) +3 (B) +2 (C) +1 (D) –1 16. 17. 18. The oxidation states of the most electronegative element in the products of the reaction, BaO2 will dil. H2SO4 is [1991, 1M] (A) 0 and –1 (B) –1 and –2 (C) –2 and 0 (D) –2 and –1 Read the following statement and explanation and answer as per the options given below : STATEMENT(S) : In the titration of Na2CO3 with HCl using methyl orange indicator, the volume required at the equivalence point is twice that of the acid required using phenolphthalein indicator. EXPLANATION (E) : Two moles of HCl are required for the complete neutralization of one mole of Na2CO3. [1991, 2M] (A) Both S and E are true, and E is the correct explanation of S. (B) Both S and E are true, and E is not the correct explanation of S. (C) S is true but E is false. (D) S is false but E is true. 19. The number of moles of KMnO4 that will be needed to react completely with one mole of ferrous oxalate in acidic solution is [1997C, 1M] 3 2 (A) (B) 5 5 4 (D) 1 (C) 5 20. The normality of 0.3 M phosphorous acid [1999, 2M] (H3PO3) is, (A) 0.1 (B) 0.9 (C) 0.3 (D) 0.6 21. The oxidation number of sulphur in S8, S2F2, H2S [1999, 2M] respectively, are (A) 0, +1 and –2 (B) +2, +1 and –2 (C) 0, +1 and +2 (D) –2, +1 and –2 22. Amongst the following identify the species with [2000S] an atom in +6 oxidation state 23. (A) (B) (C) (D) C 2O 24− H+ 2 16 5 2 5 5 16 16 16 2 2 5 (C) NiF62− (D) CrO2Cl2 The reaction, example of (A) oxidation reaction (B) reduction reaction (C) disproportionation reaction (D) decomposition reaction [2001 S] 24. An aqueous solution of 6.3 g oxalic acid dihydrate is made up to 250 ml. The volume of 0.1 N NaOH required to completely neutralize [2001 S] 10 ml of this solution is (A) 40 ml (B) 20 ml (C) 10 ml (D) 4 ml 25. In the standardization of Na2S2O3 using K2Cr2O7 by iodometry, the equivalent weight of K2Cr2O7 is: [2001 S] (A) (molecular weight)/2 (B) (molecular weight)/6 (C) (molecular weight)/3 (D) same as molecular weight MnO −4 + C 2O 24− + H + → Mn 2+ + CO 2 + H 2O MnO −4 (B) Cr (CN)36− 3ClO–(aq) → ClO3− (aq) + 2Cl − (aq), is an For the redox reaction : the correct coefficients of the reactants for they balanced reaction are [1992, 1M] (A) MnO −4 3 MOLE CONCEPT & STOICHIOMETRY 26. How many moles of electron weigh one [2002S] kilogram ? 1 (A) 6.023 × 1023 (B) × 1031 9.108 6.023 1 × 1054 (D) × 108 (C) 9.108 9.108 × 6.023 27. Which has maximum number of atoms ? [2003S] (A) 24g of C (12) (B) 56g of Fe (56) (C) 27g of Al (27) (D) 108g of Ag (108) 28. Mixture X = 0.02 mol of [Co(NH3)5 SO4]Br and 0.02 mol of [Co(NH3)5 Br]SO4 was prepared in [2003S] 2 litre of solution. 1 litre of mixture X + excess AgNO3 → Y 1 litre of mixture X + excess BaCl2 → Z No. of moles of Y and Z are (A) 0.01, 0.01 (B) 0.02, 0.01 (C) 0.01, 0.02 (D) 0.02, 0.02 32. The reaction of white phosphorus with aqueous NaOH gives phosphine along with another phosphorus containing compound. The reaction type ; the oxidation states of phosphorus phosphine and the other product are [2012] respectively (A) redox reaction ; –3 and –5 (B) redox reaction ; +3 and +5 (C) disproportionation reaction ; –3 and +5 (D) disproportionation reaction ; –3 and +3 33. Hydrogen peroxide in its reaction with KIO4 and NH2OH respectively, is acting as a [2014] (A) reducing agent, oxidising agent (B) reducing agent, reducing agent (C) oxidising agent, oxidising agent (D) oxidising agent, reducing agent ASSERTION‐REASON TYPE 1. 29. The pair of the compounds in which both the metals are in the highest possible oxidation [2004S] state is (A) [Fe(CN)6]3–, [Co(CN)6]3– (B) CrO2Cl2, MnO −4 (C) TiO3, MnO2 (D) [Co(CN)6]3–, MnO3 30. Consider a titration of potassium dichromate solution with acidified Mohr’s salt solution using diphenylamine as indicator. The number of moles of Mohr’s salt required per mole of [2007] dichromate is (A) 3 (B) 4 (C) 5 (D) 6 31. Which ordering of compounds is according to the decreasing order of the oxidation state of [2012] nitrogen ? (A) HNO3, NO, NH4Cl, N2 (B) HNO3, NO, N2, NH4Cl (C) HNO3, NH4Cl, NO, N2 (D) NO, HNO3, NH4Cl, N2 STATEMENT-1 : Pb4+ compounds are stronger oxidizing agents than Sn+ compounds. and STATEMENT-2 : The higher oxidation states for the group 14 elements are more stable for the heavier members of the group due to inert [2008] pair effect. (A) STATEMENT-1 is True, STATEMENT-2 is True; STATEMENT-2 is a correct explanation for STATEMENT-1. (B) STATEMENT-1 is True, STATEMENT-2 is True; STATEMENT-2 is NOT a correct explanation for STATEMENT-1. (C) STATEMENT-1 is True, STATEMENT-2 is False. (D) STATEMENT-1 is False, STATEMENT-2 is True. ONE OR MORE THAN ONE CORRECT ANSWERS 1. Reduction of the metal centre in aqueous [2011] permanganate ion involves (A) 3 electrons in neutral medium (B) 5 electrons in neutral medium (C) 3 electrons in alkaline medium (D) 5 electrons in acidic medium 4 2. 39 YEARS TOPIC- WISE JEE Advanced Questions with Solutions For the reaction – I + ClO 3− 5. − + H 2 SO 4 → Cl + HSO 4− + I2 The correct statement(s) in the balanced [2014] equation is/are :(A) Stoichiometric coefficient of HSO −4 is 6 ANALYTICAL & DESCRIPTIVE QUESTIONS (B) Iodide is oxidized (C) Sulphur is reduced (D) H2O is one of the products 1. What weight of AgCl will be precipitated when a solution containing 4.77 g of NaCl is added to a [1978] solution of 5.77 g of AgNO3 ? 2. One gram of an alloy of aluminium and magnesium when treated with excess of dil. HCl forms magnesium chloride, aluminium chloride and hydrogen. The evolved hydrogen, collected over mercury at 0°C has a volume of 1.20 litres at 0.92 atm. pressure. Calculate the composition of the alloy. [H = 1, Mg = 24, Al = 27] [1978] 3. Igniting MnO2 converts it quantitatively to Mn3O4. A sample of pyrolusite is of the following composition : MnO2 80%, SiO2 and other inert constituents 15%, rest being water. The sample is ignited in air to constant weight. What is the percentage of Mn in the ignited sample ? [O = 16, Mn = 54.9] [1978] 4. 4.215 g of a metallic carbonate was heated in a hard glass tube and the CO2 evolved was found to measure 1336 ml at 27°C and 700 mm pressure. What is the equivalent weight of the [1979] metal ? 5. (a) 5.5 g of a mixture of FeSO4 . 7H2O and Fe2(SO4)3. 9H2O requires 5.4 ml of 0.1 N KMnO4 solution for complete oxidation. Calculate the number of gram mole of hydrate ferric sulphate in the mixture. (b) The vapour density (hydrogen = 1) of a mixture consisting of NO2 and N2O4 is 38.3 at 26.7°C. Calculate the number of moles of [1979] NO2 in 100 g of the mixture. MATRIX MATCH TYPE 1. The unbalanced chemical reactions given in List I show missing reagent or condition (?) which are provided in List II. Match List I with List II and select the correct answer using the [2013] code given below lists : List-II List-I ? 1. NO P. PbO2 + H2SO4 → PbSO4 + O2 + other product ? Q. Na2S2O3 + H2O → NaHSO4 + other product 2. I2 ? R. N2H4 → N2 + other product 3.Warm ? → Xe + other product S. XeF2 Codes : P Q R (A) 4 2 3 (B) 3 2 1 (C) 1 4 2 (D) 3 4 2 4. Cl2 S 1 4 3 1 FILL IN THE BLANKS 1. The compound YBa2Cu3O7, which shows super-conductivity, has copper in oxidation state …………, assume that the rare earth element yttrium is in its usual +3 oxidation [1994, 1M] state. The modern atomic mass unit is based [1980] on ………… 2. The total number of electrons present in 18 ml [1980] of water is ………… 3. 3g of a salt of molecular weight 30 is dissolved in 250 g of water. The molality of the solution [1983, 1M] is ………… 4. The weight of 1 × 1022 molecules of [1991, 1M] CuSO4.5H2O is ………… 5 MOLE CONCEPT & STOICHIOMETRY 6. 7. 5 ml of a gas containing only carbon and hydrogen were mixed with an excess of oxygen (30 ml) and the mixture exploded by means of an electric spark. After the explosion, the volume of the mixed gases remaining was 25 ml. on adding a concentrated solution of potassium hydroxide, the volume further diminished to 15 ml of the residual gas being pure oxygen. All volumes have been reduced to N.T.P. Calculate the molecular formula of the hydrocarbon gas. [1979] In the analysis of 0.005 g sample of feldspar. a mixture of chloride of sodium and potassium is obtained which weighs 0.1180 g. Subsequent treatment of mixed chlorides with silver nitrate gives 0.2451 g of silver chloride. What is the percentage of sodium oxide and potassium oxide [1979] in feldspar. 8. A compound contains 28 percentage of nitrogen and 72 percent of metal by weight. 3 atoms of metal combine with 2 atoms of N. [1980] Find the atomic weight of metal. 9. Find the equivalent weight of H3PO4 in the [1980] reaction : Ca(OH)2 + H3PO4 = CaHPO4 + 2H2O 10. (i) A sample of MnSO4 . 4H2O is strongly heated in air. The residue is Mn3O4. (ii) The residue is dissolved in 100 ml of 0.1 N FeSO4 containing dilute H2SO4. (iii) The solution reacts completely with 50 ml of KMnO4 solution. (iv) 25 ml of the KMnO4 solution used in step (iii) requires 30 ml of 0.1 N FeSO4 solution for complete reaction. Find the amount of MnSO4 . 4H2O present in the [1980] sample. 11. (a) One litre of a sample of hard water contains 1 mg of CaCl2 and 1 mg of MgCl2. Find the total hardness in terms of parts of CaCO3 per 106 parts of water by weight. (b) A sample of hard water contains 20 mg of Ca++ ions per litre. How many milli-equivalent of Na2CO3 would be required to soften 1 litre of the sample ? (c) 1 gm of Mg is burnt in a closed vessel which contains 0.5 gm of O2. (i) Which reactant is left in excess ? (ii) Find the weight of the excess reactants ? (iii) How many milliliters of 0.5 N H2SO4 will dissolve the residue in the vessel. [1980] 12. A hydrocarbon contains 10.5 g of carbon per gram of hydrogen. 1 litre of the vapour of the hydrocarbon at 127°C and 1 atmosphere pressure weighs 2.8 g. Find the molecular [1980] formula. 13. Find (i) The total number of neutrons and (ii) The total mass of neutron in 7 mg of 14C. (Assume that mass of neutron = mass of [1980] hydrogen atom) 14. A mixture contains NaCl and unknown chloride MCl. (i) 1g of this is dissolved in water. Excess of acidified.AgNO3 solution is added to it. 2.567 g of white ppt. is formed. (ii) 1g of original mixture is heated to 300°C. Some vapours come out which are absorbed in acidified AgNO3 solution. 1.341 g of white precipitate was obtained. Find the molecular weight of unknown [1980] chloride. 15. A 1.00 gm sample of H2O2 solution containing X per cent H2O2 by weight requires X ml of a KMnO4 solution for complete oxidation under acidic conditions. Calculate the normality of the [1981, 3M] KMnO4 solution. 16. Balance the following equations. (i) Cu2O + H+ + NO3− = Cu2+ + NO + H2O [1981, 1M] (ii)K4[Fe(CN)6] + H2SO4 + H2O = K2SO4 + FeSO4 + (NH4)2 SO4 + CO [1981, 1M] (iii)C2H5OH + I2 + OH– = CHI3 + HCO3− + I– + H2O [1981, 1M] 6 17. 18. 39 YEARS TOPIC- WISE JEE Advanced Questions with Solutions 21. MnO −4 + 5Fe2+ + 8H+ → Mn2+ + 5Fe3+ + 4H2O A 10 ml. sample of hydroxylamine solution was diluted to 1 litre. 50 ml. of this diluted solution was boiled with an excess of iron (III) solution. The resulting solution required 12 ml. of 0.02M KMnO4 solution for complete oxidation of iron (II). Calculate the weight of hydroxylamine in one litre of the original solution. (H = 1, N = 14, O = 16, K = 39, Mn = 55, Fe = 56 [1982, 4M] 22. Five ml of 8N nitric acid, 4.8 ml of 5N hydrochloric acid are mixed together and made upto 2 litre. Thirty ml. of this acid mixture exactly neutralize 42.9 ml of sodium carbonate solution containing one gram of Na2CO3.10H2O in 100 ml. of water. Calculate the amount in gram of the sulphate ions in [1985, 4M] solution. 23. Arrange the following in increasing oxidation [1986, 1M] number of iodine. I2, HI, HIO4, ICl 24. (i) What is the weight of sodium bromate and molarity of solution when the half-cell reaction is The density of a 3M sodium thiosulphate solution (Na2S2O3) is 1.25 g per ml. Calculate (i) the percentage by weight of sodium thiosulphate, (ii) the mode fraction of sodium thiosulphate and (iii) the molalities of Na+ and S2O32− ions. 19. 20. 2.68 × 10–3 moles of a solution containing an ion Hydroxylamine reduces iron (III) according to the equation : 2NH2OH + 4Fe3+ → N2O(g) ↑ + H2O + 4Fe2 + 4H+ Iron (II) thus produced is estimated by titration with a standard permanganate solutions. The reaction is : An+ acquire 1.61 × 10–3 moles of MnO −4 for the oxidation of An+ to AO3− in acid medium. What is the value of n ? [1983, 5M] 4.08 g of a mixture of BaO and an unknown carbonate MCO3 was heated strongly. The residue weighed 3.64 g. This was dissolved in 100 ml of 1N HCl. The excess acid required 16 ml of 2.5 N NaOH solution for complete neutralization. Identify the metal M. (At. Wt. H = 1, C = 12, O = 16, Cl = 35.5, [1983, 4M] Ba = 138) BrO 3− + 6H + + 6e − → Br − + 3H 2 O (ii) What would be the weight as well as molarity if the half-cell reaction is : 2 BrO3− + 12H + + 10e − → Br2 + 6H 2O [1987, 5M] 25. A sugar syrup of weight 214.2 g contains 34.2 g of sugar (C12H22O11). Calculate : (i) mole concentration and (ii) mole [1988, 5M] fraction of sugar in the syrup. 26. A sample of hydrazine sulphate (N2H6SO4) was dissolved in 100 ml. of water, 10 ml of this solution was reacted with excess of ferric chloride solution and warmed to complete the reaction. Ferrous ion formed was estimated and it required 20 ml. of M/50 potassium permanganate solution. Estimate the amount of hydrazine sulphate in one litre of the solution. Reaction : 4Fe3+ + N2H4 → N2 + 4Fe2+ + 4H+ Complete and balance the following reactions : (i) Zn + NO3− = Zn 2+ + NH +4 [1983, 1M] (ii) Cr2O 72− + C 2 H 4O = C 2 H 4O 2 + Cr 3+ [1983, 1M] (iii) HNO3 + HCl = NO + Cl2 [1983, 1M] (iv) Ce3+ + S2O82− = SO 24− + Ce 4+ (v) Cl2 + OH– = Cl– + ClO– [1983, 1M] [1983, 1M] (vi) Mn2+ + PbO2 → MnO −4 + H2O [1986, 1M] (vii) S + OH– → S2– + S2O32− [1986, 1M] (viii) ClO3− + I − + H 2SO 4 → Cl − + HSO −4 [1983, 1M] (ix) Ag+ + AsH3 → H3AsO3 + H+ [1986, 1M] [1984, 2M] MnO 4− + 5Fe2+ + 8H + → Mn 2+ + 5Fe3+ + 4H 2O [1988, 3M] 7 MOLE CONCEPT & STOICHIOMETRY 27. 28. An equal volume of a reducing agent is titrated separately with 1M KMnO4 in acid neutral and alkaline media. The volumes of KMnO4 required are 20 ml. in acid, 33.4 ml. neutral and 100 ml. in alkaline media. Find out the oxidation state of manganese in each reduction product. Give the balanced equations for all the three half reactions. Find out the volume of 1M K2Cr2O7 consumed; if the same volume of the reducing agent is titrated in [1989, 5M] acid medium. A mixture of H2C2O4 (oxalic acid) and NaHC2O4 weighing 2.02 g was dissolved in water and solution made upto one litre. Ten milliliters of the solution required 3.0 ml. of 0.1 N sodium hydroxide solution for complete neutralization. In another experiment, 10.0 ml. of the same solution, in hot dilute sulphuric acid medium. require 4.0 ml. of 0.1 N potassium permanganate solution for complete reaction. Calculate the amount of H2C2O4 and NaHC2O4 in the mixture. [1990, 5M] 29. A solid mixture (5.0 g) consisting of lead nitrate and sodium nitrate was heated below 600°C until the weight of the residue was constant. If the loss in weight is 28.0 per cent, find the amount of lead nitrate and sodium [1990, 4M] nitrate in the mixture. 30. Calculate the molality of 1 litre solution of 93% H2SO4 (weight/volume). The density of the [1990, 1M] solution is 1.84 g/ml. 31. A solution of 0.2g of a compound containing Cu2+ and C 2O 24− ions on titration with 0.02 M 32. A 1.0 g sample of Fe2O3 solid of 55.2% purity is dissolved in acid and reduced by heating the solution with zinc dust. The resultant solution is cooled and made upto 100.0 ml. An aliquot of 25.0 ml of this solution requires 17.0 ml of 0.0167 M solution of an oxidant for titration. Calculate the number of electrons taken up by the oxidant in the reaction of the above [1991, 4M] titration. 33. A 2.0 g sample of a mixture containing sodium carbonate, sodium bicarbonate and sodium sulphate is gently heated till the evolution of CO2 ceases. The volume of CO2 at 750 mm Hg pressure and at 298 K is measured to be 123.9 ml. A 1.5g of the same sample requires 150 ml. of (M/10) HCl for complete neutralization. Calculate the % composition of [1992, 5M] the components of the mixture. 34. One gram of commercial AgNO3 is dissolved in 50 ml. of water. It is treated with 50 ml. of a KI solution. The silver iodide thus precipitated is filtered off. Excess of KI in the filtrate is titrated with (M/10) KIO3 solution in presence of 6M HCl till all I– ions are converted into ICl. It requires 50 ml. of (M/10) KIO3 solution. 20 ml. of the same stock solution of KI requires 30 ml. of (M/10)KIO3 under similar conditions. Calculate the percentage of AgNO3 in the sample. (Reaction : KIO3 + 2KI + 6HCl → 3ICl + 3KCl + [1992, 4M] 3H2O) 35. Upon mixing 45.0 ml. of 0.25 M lead nitrate solution with 25.0 ml of 0.10 M chromic sulphate solution, precipitation of lead sulphate takes place ? How many moles of lead sulphate are formed. Also, calculate the molar concentration of the species left behind in the final solution. Assume that lead sulphate is [1994, 2M] completely insoluble. 36. The composition of a sample of Wustite is Fe0.39 O1.00. What percentage of the iron is [1994, 2M] present in the form of Fe (III) ? KMnO4 in presence of H2SO4 consumers 22.6 ml. of the oxidant. The resultant solution is neutralized with Na2CO3, acidified with dil. acetic acid and treated with excess KI. The liberated iodine requires 11.3 ml of 0.05 M Na2S3O3 solution for complete reduction. Find out the molar ratio of Cu2+ to C 2O 24− in the compound. Write down the balanced redox reactions involved in the above titrations. [1991, 5M] 8 37. 38. 39. 39 YEARS TOPIC- WISE JEE Advanced Questions with Solutions –2 8.0575 × 10 kg of Glauber’s salt is dissolved in water to obtain 1 dm3 of a solution of density 1077.2 kg m–3. Calculate the molarity, molality and mole fraction of Na2SO4 in the solution. [1994, 3M] A 3.00 g sample containing Fe3O4, Fe2O3 and an inert impure substance, is treated with excess of KI solution in presence of dilute H2SO4. The entire iron is converted into Fe2+ along with the liberation of iodine. The resulting solution is diluted to 100 ml. A 20 ml of the diluted solution requires 11.0 ml of 0.5 M Na2S2O3 solution to reduce the iodine present. A 50 ml of the diluted H2SO4 medium for the oxidation of Fe2+. Calculate the percentages of Fe2O3 and Fe3O4 in [1996, 5M] the original sample. An aqueous solution containing 0.10 g KIO3 (formula weight = 214.0) was treated with the an excess of KI solution. The solution was acidified with HCl. The liberated I2 consumed 45.0 mL of thiosulphate solution to decolourise the blue starchiodine complex. Calculate the molarity of the [1998, 5M] sodium thiosulphate solution. 40. How many millilitres of 0.5 M H2SO4 are needed to dissolve 0.5 g of copper(II) [1999, 3M] carbonate? 41. A plant virus is found to consist of uniform cylindrical particles of 150 Å in diameter and 5000 Å long. The specific volume of the virus is 0.75 cm3/g. If the virus is considered to be a single particle, find its molar mass. [1999, 3M] 42. Hydrogen peroxide solution (20 ml) reacts quantitatively with a solution of KMnO4(20 ml) acidified with dilute H2SO4. The same volume of the KMnO4 solution is just decolourised by 10 ml of MnSO4 in neutral medium simultaneously forming a dark brown precipitate of hydrated MnO2. The brown precipitate is dissolved in 10 ml of 0.2 M sodium oxalate under boiling condition in the presence of dilute H2SO4. Write the balanced equations involved in the reactions and calculate the [2001, 5M] morality of H2O2. 43. Calculate the molarity of water if its density is [2003, 2M] 1000 kg/m3. 44. The oxidation number of Mn in the product of alkaline oxidative fusion of MnO2 is [2009] 45. A student performs a titration with different burettes and finds titre values of 25.2 mL, 25.25 mL and 25.0 mL. The number of significant figures in the average titre value is [2010] 46. Silver (atomic weight = 108 g mol–1) has a density of 10.5 g cm–3. The number of silver atoms on a surface of area 10–12 m2 can be expressed in scientific notation as y × 10x. The [2010] value of x is 47. Among the following, the number of elements showing only one non-zero oxidation state is O, Cl, F, N. P, Sn, Tl, Na, TI [2010] 48. Reaction of Br2 with Na2CO3 in aq. solution gives sodium bromide and sodium bromate with evolution of CO2 gas. The number of sodium bromide molecules involved in the [2011] balanced chemical equation is. 49. The difference in the oxidation numbers of the two types of sulphur atoms in Na2S4O6 is. [2011] 50. A decapeptide (mol. wt. 796) on complete hydrolysis gives glycine (mol. wt. 75), alanine and phenylalanine. Glycine contributes 47.0% to the total weight of the hydrolysed products. The number of glycine units present in the [2011] decapeptide is. 51. The volume (in mL) of 0.1 M AgNO3 required for complete precipitation of chloride ions present in 30 mL of 0.01 M solution of [Cr(H2O)5Cl]Cl2, as silver chloride is close to [2011] 9 MOLE CONCEPT & STOICHIOMETRY 52. 29.2% (w/w) HCl stock solution has a density of 1.25 g mL–1. The molecular weight of HCl is 36.5 g mol–1. The volume (mL) of stock solution required to prepare a 200 mL solution [2012] of 0.4 M HCl is. 54. If the value of Avogadro number is 6.023 × 1023 mol–1 and the value of Boltzmann constant is 1.380 × 10–23 J K–1, then the number of significant digits in the calculated [2014] value of the universal gas constant is 53. Consider the following list of reagents : Acidified K2Cr2O7, alkaline KMnO4, CuSO4, H2O2, Cl2, O3, FeCl3, HNO3 and Na2S2O3. The total number of reagents that can oxidise [2014] aqueous iodide to iodine is 55. In neutral or faintly alkaline solution, 8 moles of permanganate anion quantitatively oxidize thiosulphate anions to produce X moles of a sulphur containing product. The magnitude of [2016] X is 10 39 YEARS TOPIC- WISE JEE Advanced Questions with Solutions ANSWERS ¾ Only One Correct Answer 1.(D) 2.(C) 3.(A) 4.(A) 5.(C) 6.(A) 7.(A) 8.(D) 9.(C) 10.(C) 11.(A) 12.(B) 13.(B) 14.(D) 15.(C) 16.(B) 17.(B) 18.(A) 19.(A) 20.(D) 21.(A) 22.(D) 23.(C) 24.(A) 25.(B) 26.(D) 27.(A) 28.(A) 29.(B) 30.(D) 31. (B) 32. (C) 33. (A) 4. 4.14g 5. + 3. 59.36 % 4. 8.38 6. CH4 7. Na2O = 3.58 %, K2O = 10.62 % ¾ Assertion‐Reason Type 1. (C) ¾ One or More than One Correct Answers 1. (A,C,D) 2. (A,B,D) ¾ Matrix Match Type 1. (D) ¾ Fill in the Blanks 2. 6.02 × 1023 1. Carbon 3. 0.4 7 3 ¾ Analytical & Descriptive Question 1. 4.87 g 2. Al 54.87 %, Mg 45.13 % –3 5. (a) 9.5 × 10 gram mole, (b) 0.437 8. 24 9. 49 10. 1.338 gm 11. (a) 1.95 parts ; (b) 1 milli equivalents ; (c) (i) Mg, (ii) 0.25, (iii) 62.5 ml 13. 3.5 × 10–3 g 14. 53.53 12. C7H8 18. (i) 37.92 ; (ii) 0.065 ; (iii) 7.74, 3.87 23. HI < I2 < ICI < HIO4 15. 0.588 N 17. 39.6 g l–1 19. Ca 21. 2 22. 6.3648 g 24. (i) 1.446 gm, 0.112 M ; (ii) 1.7532 g, 0.1334 M 25. (i) 0.56 ; (ii) 0.0999 26. 6.5 g 27. +2, +4, +6, 16.66 ml 28. 1.12 g, 0.90 g 30. 10.43 31. 1:2 33. Na2CO-26.5%, Na2SO4-31.5% 32. 6 29. 3.324 g, 1.676 g 34. 85% 35. 0.0075, Pb2+ = 0.05357 M, NO3− = 0.3214 M, Cr3+ = 0.0714 M 36. 15.05% 37. 0.25 M, 0.24 mg, 4.3 × 10–3 38. 49.33%, 34.8% 39. 0.062 40. 8.097 l ml 7 41. 7.09 × 10 42. 0.1 43. 55.55 M 44. 6 45. 3 46. 7 47. 2 48. 5 49. 5 50. 6 51. 6 52. 8 53. 7 54. 4 55. 6 11 MOLE CONCEPT & STOICHIOMETRY SOLUTIONS Ratio of molecules of oxygen : nitrogen Only One Correct Answer 1. 4Al + 3O2 → 2Al2O3 At. wt. of Al = 27 g = Q 4 × 27 g of Al reacts with = 3 × 32 g of oxygen 3 × 32 ∴ 27 g of Al reacts with = × 27 g of 4 × 27 oxygen = 24 g of oxygen 2. No. of Nitrogen atoms = No. of oxygen atoms = 6. 1 2Ag + O 2 2 (residue) Mol. wt. of Ag2CO3 = 107 × 2 + 12 + 16 × 3 = 274 g ∴ 274 g of Ag2CO3 on heating gives = 2 × 107 = 214 g of Ag ∴ 2.76 g of Ag2CO3 on heating gives 214 = × 2.76 274 = 2.16 g of Ag Mass 28 = =2 M. wt. 14 Mass 80 = =5 M. wt. 16 (a) 18 g of H2O = 6.02 × 1023 molecules of H2O ∴36 g of H2O = 2 × 6.02 × 1023 molecules of H2O (b) 28 g of CO = 6.02 × 1023 molecules of CO2 (c) 46 g of C2H5OH = 6.02 × 1023 molecules of C2H5OH (d) 108 g of N2O5 = 6.02 × 1023 molecules of N2O5 1 ∴ 54 g of N2O5 = × 6.02 × 10 23 molecules of 2 N2O5 ∴ 36 g water has highest number of molecules. 4. No. of e– in C = 6 and in O = 8 ∴ Total no. of e– in CO2 = 6 + 8 × 2 = 22 5. Let mass of oxygen = 1g Let mass of Nitrogen = 4g Mol. wt. of N2 = 28g, Mol. wt. of O2 = 32g Q 28 g of N2 has = 6.02 × 1023 molecules Q 4g of N2 has = 6.02 × 10 23 × 4 molecules 28 6.02 × 1023 molecules 7 ∴ 32 g of O2 has = 6.02 × 1023 molecules = ∴ 1g of O2 has = 6.02 × 10 23 6.02 × 10 23 ×1 = 32 32 ∆ Ag2CO3 Ag2O + CO2 → ∆ ↓ ∴ Formula of compound is N2O5. 3. 6.02 × 10 23 / 32 = 7 : 32 6.02 × 10 23 / 7 7. M : e − + MnO 4− → MnO 24− E.wt = Mol. wt M = =M No. of e − 1 8. Tips/Formula (i) Write balance chemical equation for chemical change. (ii) Find limiting agent. (iii) Amount of product formed will be determined by amount of product formed. Method : 3BaCl2 + 2Na3PO4 → Ba3(PO4)2 + 6NaCl 0.5 0.2 Limiting reagent is Na3PO4(0.2 mol), which gives 0.1 mol of Ba2(PO4)2. 9. Tips/Formula (i) Find oxidation state of N in N2H4. (ii) Find change in oxidation number with the help of number of electrons given out during formation of compound Y. Method : N2H4 → Y + 10 e–. O.S. of N in N2H4 : 2x + 4 = 0 ⇒ x = –2 12 39 YEARS TOPIC- WISE JEE Advanced Questions with Solutions The 2, nitrogen atoms will balance the charge of 10 e–. Hence oxidation state of N will increase by +5, i.e. from –2 to +3. 10. Tips/Formula : The sum of oxidation states of all atoms in compound is zero. Method : O.S. of H = +1, O.S of O = –2 ; ∴ for CH2O. x + 2 + (–2) = 0 ⇒ x = 0 11. Tips/Formula : Define molality Method : A molal solution is one which contains one mole of solute per 1000 g of solvent. 12. Tips/Formula : Sum of oxidation state of all atoms in compound is zero. Method : Method : (A) Molarity – Moles of solute/volume of solution in L. (B) Normality – gm equivalents of solute/volume of solution in L. (C) Formality – formula wt./volume of solution in L. (D) Molality – Moles involve volume term. Q Molality does not involve volume term. ∴ It is independent of temperature. 15. 2 + 2 (2 + x – 4) = 0 or x = 2 – 1 ⇒ x = + 1 16. Tips/Formula : (i) Write balance chemical equation for given changes. (ii) Identify most electronegative element and find its oxidation state. Method : BaO2 + H2SO4 → BaSO4 + H2O2 Oxygen being the most electronegative element in the reaction has the oxidation states of –1 (in H2O2) and –2 (in BaSO4) 17. Tips/Formula : Write reaction for titration between Na2CO3 and HCl. Method : Na 2CO3(aq ) + HCl(aq ) → NaHCO3 + NaCl( aq ) [Fe(H2O)5(NO)+]2+ SO 24− ; x + 5 × 0 + 0 = +2 13. Tips/Formula : (i) Equivalent weight Molecular Weight = Change in oxidation state (ii) Find oxidation state of Mn in MnSO4 and in the choice in which the choice in which the oxidation state is 2, will have equivalent weight equal to molecular weight. Method : For equivalent weight of MnSO4 to be half of its molecular weight, change in oxidation state must be equal to 2. It is possible only when oxidation state of Mn is +4 because oxidation state of Mn in MnSO4 is +2. So, MnO2 is correct answer. 14. Tips/Formula : (i) Volume is substance changes with temperature and mass is not effected by change in temperature. (ii) Find expression which does not have volume term in it. ( no colour with HPh ) ( yellow colour with HPh ) NaHCO3 + ( yellow colour second half with methyl orange) HCl → ( Half neutralisation ) NaCl + H 2O + CO 2 ( red colour with methyl neutralization orange) From these reaction it is clear that (i) 2 moles of HCl are requires for complete neutralization of Na2CO3. (ii) Titre value using phenolphthalein corresponds only to neutralization of Na2CO3 to NaHCO3, i.e. half of value required by Na2CO3 solution. (iii) Titre value using methyl orange corresponds to complete neutralization of Na2CO3. ∴ Both S and E are correct but S is not correct explanation of E.
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