Table Of Content111
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Problems in
Chemistry
111
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Problems in
Chemistry
Ranjeet Shahi
ARIHANT PRAKASHAN (Series), MEERUT
Arihant Prakashan (Series), Meerut
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PREFACE
This work is the result of my teaching the JEE aspirants over the post
decade and a half. Often I have found that the students mess up with
the chemical reactions given in the problem and get themselves
entangled into them. The reason is that they are not able to
distinguish the relationships between the various chemical principles
and concepts. This book is an effort to make them master the
fundamentals of Chemistry through problems-solving, and apply
them intelligently to arrive at a correct solution.
The problems included in the book with their solutions, aim to give
you the mastery required for solving the intricate problems asked in
the exams such as JEE.
Critical analysis of the situation is required whatever be format of the
questions. This book just gives emphasis on this, and it is hoped that it
will give a boost to all the meritorious and hard-wroking students.
I shall like to thank Mr Yogesh Chand Jain, Chairman, Arihant Group,
for bringing the book in this nice form.
Suggestions for further improvement of the book are welcome.
Ranjeet Shahi
CONTENTS
1. Mole Concept 3
2. Acid-Base Titration 7
3. Redox Titration 12
4. Gaseous State 16
5. Thermochemistry 20
6. Thermodynamics 26
7. Atomic Structure 33
8. Chemical Bonding 36
9. Chemical Equilibrium 39
10. Ionic Equilibrium 47
11. Electrochemistry 57
12. Chemical Kinetics 67
13. Colligative Properties 75
14. Solid State 78
15. Surface Chemistry 80
16. Reaction Mechanism 81
17. Stereochemistry 95
18. Hydrocarbons 103
19. Alkyl Halides 120
20. Alcohols and Ethers 133
21. Aldehydes and Ketones 161
22. Carboxylic Acids and Its Derivatives 193
23. Amines 213
24. Aromatic Compounds 216
25. Carbohydrates, Amino Acids and Polymers 264
26. Miscellaneous 265
27. Qualitative Analysis 271
28. Co-odination Compounds 278
29. Representative Elements 285
30. Metallurgy 292
Solutions 295
Problems in Chemistry 3
M C
OLE ONCEPT
PROBLEM1 Acrystallinehydratedsaltonbeingrenderedanhydrous,loses45.6%ofitsweight.The
percentage compositionofanhydrous saltis: Al=10.5%,K=15.1%,S=24.8%andO=49.6%.Find
the empirical formula of the anhydrous and crystalline salt.
PROBLEM2 HowmuchquantityofzincwillhavetobereactedwithexcessofdiluteHClsolutionto
produce sufficient hydrogen gas for completely reacting with the oxygen obtained by decomposing
5.104 g of potassium chlorate?
PROBLEM3 A 1.85 g sample of mixture of CuCl and CuBr was dissolved in water and mixed
2 2
thoroughlywith1.8gportionofAgCl.Afterreaction,thesolidwhichnowcontainAgClandAgBrwas
filtered, dried and weighed to be 2.052 g. What was the % by weight of CuBr in the mixture?
2
PROBLEM4 1.0gofasamplecontainingNaCl,KClandsomeinertimpurityisdissolvedinexcessof
waterandtreatedwithexcessofAgNO solution.A2.0gprecipitateofAgClseparateout.Alsosample
3
is 23% by mass in sodium. Determine mass percentage ofKClin the sample.
PROBLEM5 A one gram sample containing CaBr , NaCl and some inert impurity was dissolved in
2
enough water and treated with excess of aqueous silver nitrate solution where a mixed precipitate of
AgCl and AgBr weighing 1.94 g was obtained. Precipitate was washed, dried and shaken with an
aqueoussolutionofNaBrwhereallAgClwasconvertedintoAgBr.Thenewprecipitatewhichcontain
only AgBr now weighed to be 2.4 g. Determine mass percentage ofCaBr and NaCl in the original
2
sample.
PROBLEM6 SulphurcombineswithoxygentoformtwooxideSO andSO .If10gofSismixedwith
2 3
12gofO ,whatmassofSO andSO willbeformed,sothatneitherSnoroxygenwillbeleftattheend
2 2 3
of reaction?
PROBLEM7 An aqueous solution of ethanol has density 1.025 g/mL and it is 8.0 M. Determine
molalitymof this solution.
PROBLEM8 An aqueous solution of acetic acid has density 1.12 g/mL and it is 5.0 m. Determine
molarity (M).
PROBLEM9 Octaneisacomponentofgasoline.IncompletecombustionofoctaneproducessomeCO
alongwithCO andH O,whichreducesefficiencyofengine.Inacertaintestrun,1.0gallonofoctaneis
2 2
burnedandtotalmassofCO,CO andH Oproducedwasfoundtobe11.53kg.Calculateefficiencyof
2 2
the engine, density of octane is 2.65 kg/gallon.
PROBLEM 10 The formulaof a hydrated salt ofbariumis BaCl ⋅xH O.If1.936 g ofthis compound
2 2
gives 1.846 g of anhydrous BaSO upon treatment withH SO , calculatex.
4 2 4
PROBLEM11 A mixture of CuSO ⋅5H O and MgSO ⋅7H O was heated until all the water was
4 2 4 2
driven-off. If 5.0 g of mixture gave 3 g of anhydrous salts, what was the percentage by mass of
CuSO ⋅5H Oin the original mixture?
4 2
PROBLEM12 Asampleofclaycontain15%moisture,andrestareCaCO andnon-volatileSiO .This
3 2
onheatinglosespartofitsmoisture,butCaCO iscompletelyconvertedintoCaO.Thepartiallydried
3
