integrated syllabus foundation olympiad& www ......`75 detailed solutions for all problems of...

` 75Detailed solutionsfor all problems

of IIT Foundation &Olympiad Explorer

are available in this book

CLASS - XSolutions

CLASS - X

FOUNDATION OLYMPIAD&

IIT F

oundatio

n &

Olym

pia

d E

xplo

rer - C

hem

istry Cla

ss - X

CH

EM

IS

TR

Y

IntegratedSyllabus

CH

EM

IS

TR

Y

UNIQUE ATTRACTIONS

�

� Cross word Puzzles

� Graded Exercise

Basic Practice�

Further Practice�

Brain Nurtures�

� Numerical Problems

Conceptual Questions

� Multiple Answer Questions

� Paragraph Questions

� Assertion & Reason TypeQuestions

YOUR

COACH

India’s FIRST scientifically designed portalfor Olympiad preparation• Olympiad & Talent Exams preparation packages

Analysis Reports Previous question papers• •Free Demo Packages Free Android Mobile App• •

Get 15% discount on all packages by using the discount coupon code: KR157N

A unique opportunity to take about 50 tests per subject.

` 200

www.bmata

lent.c

om

(Free Sam

ple)

www.bmatalent.com

FOUNDATION & OLYMPIAD

CHEMISTRYCLASS - X

www.bmata

lent.c

om

(Free Sam

ple)

Published by:

Brain Mapping Academy#16–11–16/1/B, First Floor,Farhat Hospital Road,Saleem Nagar, Malakpet,Hyderabad–500 036Andhra Pradesh, India.✆ 040–65165169, 66135169E–mail: [email protected]: www.bmatalent.com

© Brain Mapping Academy

ALL RIGHTS RESERVEDNo part of this book may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise without the prior written permission of the publisher.

Publication Team

Editor: E.V.S.S. Lakshmi

Design & Typing: M. Nagender , M. Manjula

ISBN: 978-93-80299-02-0

Disclaimer

Every care has been taken by the compilers andpublishers to give correct, complete and updated information. In case there is any omission, printing mistake or anyother error which might have crept in inadvertently,neither the compiler / publisher nor any of thedistributors take any legal responsibility.

In case of any dispute, all matters are subject to the exclusive jurisdiction of the courts in Hyderabad only.www.bm

atalen

t.com

(Free Sam

ple)

PrefaceSpeed and accuracy play an important role in climbing the competitive ladder. Students have to integrate

the habit of being able to calculate and function quickly as well as efficiently in order to excel in the learning

culture. They need to think on their feet, understand basic requirements, identify appropriate information

sources and use that to their best advantage.

The preparation required for the tough competitive examinations is fundamentally different from that of

qualifying ones like the board examinations. A student can emerge successful in a qualifying examination by

merely scoring the minimum percentage of marks, whereas in a competitive examination, he has to score

high and perform better than the others taking the examination.

This book provides all types of questions that a student would be required to tackle at the foundation level.

The questions in the exercises are sequenced as Basic Practice, Further Practice, Multiple Answer Questions,

Paragraph Questions, Numerical Problems, Conceptual Questions and Brain Nurtures. Simple questions involving

a direct application of the concepts are given in Basic Practice. More challenging questions on direct application

are given in Further Practice. Questions involving higher order thinking or an open-ended approach to

problems are given in Brain Nurtures. These questions encourage students to think analytically , to be

creative and to come up with solutions of their own. Constant practice and familiarity with these questions

will not only make him/her conceptually sound, but will also give the student the confidence to face any

entrance examination with ease.

Valuable suggestions as well as criticism from the teacher and student community are most welcome and

will be incorporated in the ensuing edition.

Publisher

www.bmata

lent.c

om

(Free Sam

ple)

1. Atomic Structure .................................. 01

2. Periodic Table ....................................... 25

3. Chemical Bonding ................................ 48

4. Mole Concept & Stoichiometry ........... 71

5. Electrochemistry .................................. 92

6. Chemical Kinetics & ChemicalEquilibrium .......................................... 111

7. Acids, Bases & Salts .............................. 139

8. Compounds of Nitrogen ..................... 165

9. Compounds of Sulphur ....................... 184

10. Compounds of Chlorine ...................... 204

11. Organic Chemistry–I ........................... 224

12. Organic Chemistry–II .......................... 250

13. Metallurgy ........................................... 275

Answers ................................................ 297

Solution to Crossword Puzzles ........... 316

www.bmata

lent.c

om

(Free Sam

ple)

IIT Foundation & OlympiadExplorer Chemistry / Class - X

3. Chemical bonding © Brain Mapping Academy48

Common Misconception

1. All ionic compounds are 100% ionic.

2. HCl is an ionic compound. 3. Ice contains greater number of hydrogen

bonds than water.

1. Ionic bonds involve partial sharing and hence show partial covalent character.

2. HCl is a polar covalent compound.

3. Ice and water possess same number of hydrogen bonds than water.

Fact

SYNOPSIS

INTRODUCTION

In nature, most of the elements exist in combined state in the form of molecules. Onlyin some cases like inert gases, atom exists independently. The reason for these elementsto have independent existence is due to high stability because of completely filled octetor duplet configuration. This is the reason the atoms of other elements have tendency toattain. Stability by combining with same or other elements the above stable configurationsby means of bond formation. The process of bond formation resulting in various types ofbonds depending on the nature of participant atoms is known as chemical bonding.

Types of bonds

The various types of bonds are:

a) Ionic bond (or) electrovalent bond

b) Covalent bond

c) Coordinate bond (or) dative bond

d) Metallic bond

All these four bonds are called strong bonds. These are attractive interactions betweenthe atoms or molecules which are comparatively weaker than the bonds mentionedabove. They are called weaker bonds. Hydrogen bond and vanderwaals forces ofinteractions are examples of weaker bonds.

Ionic bond or Electrovalent bond

An ionic bond is defined as the electrostatic attractive force that exists between twooppositely charged ions in a molecule.

Force and PressureForce and Pressure1Mathematical Induction

Chapter

3CHEMICAL BONDINGCHEMICAL BONDING

Chapter

www.bmata

lent.c

om

(Free Sam

ple)



The compounds whose ions are held together by ionic or electrovalent bonds are calledionic or electrovalent compounds. These are the compounds which are formed by thecomplete transfer of one or more electrons from an electropositive element (usually ametallic element) to an electronegative element (usually a nonmetallic element).Generally an ionic bond is formed between a metal and a nonmetal.Electrovalency

The number of electrons lost or gained from the valence shell of an atom of an elementto form an ion having the stable electron octet of the nearest inert gas is called itselectrovalency. For example, calcium (2, 8, 8, 2) loses the two electrons in the valenceshell (last shell) to form Ca2+ (2, 8, 8) the stable electronic configuration of the nearestinert gas, argon. Hence electrovalency of calcium is + 2. Chlorine (2, 8, 7) gains oneelectron to form Cl� (2, 8, 8), the stable configuration of the nearest inert gas, argon.Thus, the electrovalency of chlorine is � 1.Covalent bonds

A covalent bond is defined as the bond formed by the sharing of one or more electronpair(s) between the two combining atoms in such a way that both can attain the stableelectronic configuration of the nearest inert gas. The two combining atoms may besimilar or dissimilar nonmetallic atoms. The difference between the electronegativitiesof the combining atoms should be either zero or very small. Compounds formed by thesharing of electron pairs are called covalent or molecular compounds.Non polar Covalent bond

In a bond between two identical atoms the electrons are shared equally between theatoms. No separation of charge takes place in the molecule. This type of bond is callednonpolar covalent bond.Covalency

The number of electron pairs which an atom shares with one or more atoms of the sameor different type so as to attain the stable electronic configuration of the next highernoble gas is its covalency.Types of covalent bonds

Single covalent bond

A covalent bond formed by the mutual sharing of only one pair of electrons by the twocombining atoms is called a single covalent bond. It is also known as a single bond. Thissingle bond is denoted by a single line, _____, between the two atoms. Each atomcontributes one electron for sharing.Double covalent bond

If two electron pairs are shared by the two combining atoms, it is called a double covalentbond, also called a double bond. This bond is indicated by two parallel lines, = , betweenthe two combining atoms. Each combining atom contributes two electrons for sharing.Triple covalent bond

A triple covalent bond is formed by the mutual sharing of three electron pairs betweenthe two combining atoms. This bond is denoted by three parallel lines, ≡ between thetwo atoms. It is also called a triple bond. Three electrons are contributed by each of thetwo combining atoms.

www.bmata

lent.c

om

(Free Sam

ple)



Polar covalent bond

When a covalent bond is formed between two dissimilar atoms or atoms having differentelectronegativities, then the shared pair (s) of electrons will be attracted more towardsthe more electronegative atom than towards the other. As a result, the more

electronegative atom develops a small negative charge ( )−δ and the less electronegative

atom develops a small positive charge ( )+δ , Due to the presence of these two charges,

the covalent bond between the dissimilar atoms having slightly differentelectronegativities is said to get some ionic or polar characters. Such a covalent bond iscalled polar covalent bond. Examples of polar covalent molecules are HCl, H2O, NH3,HF, HBr, HI etc.,

Polar covalent compounds are covalent when pure but became ionic when dissolved

in water.

Note:

Valence bond theory and its postulates

Lewis theory failed to explain the bond angles and the shape of the molecules, So atheory which could explain these factors was needed. Schordinger�s work laid theformation in the direction. He was the one, who introduced the concept of �wavemechanics�. A moving electron, is said to behave as both, a particle and a wave. Wavemechanics, deals with the behaviour of an electron as a wave. Schrodinger, with thehelp of wave mechanics proposed the shape of orbitals. This development led to theconcept of orbital bonding in the form of valence bond theory. This valence bond theory,was developed by Heitler and London in 1927, based on wave mechanics. Later, Paulingand Slater modified this theory.

1. Cause for the formation of a covalent bond:

A covalent bond is formed by the overlap of orbitals of one atom, with orbitals ofanother atom.

2. Conditions for overlapping of orbitals:

(i) Only an orbital with unpaired electrons is eligible for overlapping.

Eg: Outer electronic configuration of �Cl� and its block diagram is

3s 3p 3p 3px y z

In the outer shell of Cl, the orbitals 3s, 3px and 3py are completely filled withone pair of electrons in each, whereas 3pz orbital is half�filled and it is said tobe an orbital with an unpaired electron. Only such an orbital is eligible foroverlapping.

www.bmata

lent.c

om

(Free Sam

ple)



(ii) For the orbitals to overlap, the electrons in overlapping orbitals should spin inthe opposite direction.

(iii) After overlapping, the shape of the orbitals change such that a greater electrondensity appear between the nuclei of the atoms, along the internuclear axis(an imaginary line joining the nuclei of combining atoms)

E.g. During the overlap of two �p� orbitals, the size of one lobe decreases andthe other lobe stretches and increases in size. The lobes with an increasedsize, merge with each other resulting in greater electron density, along theinternuclear axis.

+

p-orbital p-orbital

p-orbital p-orbital Lobe with

reduced size

Inter nuclear

axis

A region of high electron density is formed between the nuclei of the combiningatoms. The attraction between the positive nuclei and the electron cloud, inthe region of high electron density holds the combining atoms together.

(iv) The direction of the covalent bond is in that direction in which, the overlappingorbitals have greater electron density. This is along the internuclear axis.

3. Strength of covalent bond :

The factor which decides the strength of a covalent bond is the extent of the overlap.Greater the extent of the overlap, more is the strength of a covalent bond. Theextent of the overlap depends on the shape of the orbitals. The spherical �s� orbitalscannot overlap effectively, whereas the extent of overlap in the dumbbell shaped �p�orbitals is more. So, covalent bonds involving the overlap of �s� orbitals are weaker,when compared to covalent bonds involving the overlap of �p� orbitals.

Limitations of valence bond theory

1. Since the two electrons of the shared pair constitute a covalent bond, they mustcome from two different atoms. This theory, does not give any explanation about theformation of coordinate covalent bond, in which one of the bonded atoms furnishesboth the electrons.

2. The two atoms in O2 molecule, should have close electronic shell, resembling thoseof Ne, which would give even number of electrons (paired) to the molecule, whichwill make a diamagnetic (substances which get repelled in a magnetic field. Thisphenomena is exhibited by molecules having paired electrons). But experiments showthat O2 molecule is paramagnetic (substances which are weakly attracted in a magneticfield. This phenomenon is exhibited by molecules having unpaired electrons), indicating

www.bmata

lent.c

om

(Free Sam

ple)



the presence of unpaired electrons in oxygen molecule. Valence bond theory cannotexplain this.

3. This theory does not consider the formation of an odd electron molecule or ions suchas H2

+ ion, where no pairing of electrons occur and where the molecule has only oneelectron.

Overlapping of Orbitals

s–s overlapping

The overlapping between �s� orbital of one atom and the �s� orbital of another atom iscalled s�s overlapping. This is observed in the formation of hydrogen molecule.

+

1s 1s s � s H H H2

The electron cloud of 1s orbital of one hydrogen atom overlaps with 1s orbital of anotherhydrogen atom. As a result, the 2 nuclei are brought closer and a strong bond is formed.

p–p overlapping

The overlapping between �p� orbital of one atom and the �p� orbital of another atom iscalled p�p overlapping. This type of overlapping is observed in the formation of halogenmolecules. (F2, Cl2 etc.). The unpaired dumbbell shaped �p� orbital overlaps with anothersuch p�orbital. It results in the formation of a strong bond. This overlapping is alsoknown as axial or head-on overlapping.The subsequent p�p overlapping is described as lateral or sidewise overlapping. Theseoverlappings result in weak bonds.

+

p-p overlapping(Axial)

p p

p�p overlapping can be seen in :F2, Cl2, Br2, I2, O2, N2, etc.,

s–p overlapping

The overlapping between �s� orbital of one atom and the �p� orbital of another atom iscalled �s�p� overlapping. This type of overlapping is observed in hydrogen halide molecules.The spherical �s� orbital overlaps with the dumbbell shaped p�orbital.

+

p s-p overlappings

s�p overlapping can be seen in HF, HCl, HBr, HI, H2S, H2Se, H2Te.Order of strength of overlapping : p�p > s�p > s�s.

www.bmata

lent.c

om

(Free Sam

ple)



Sigma bond ( σ bond)

A sigma bond is formed by an axial or head-on overlapping of pure atomic orbitals. It isan end to end overlap. Sigma bonds are represented by the Greek letter σ .

A strong bond is formed in all sigma bonds. In multiple bonds, one must be a sigma bondand the rest are pi bonds.

Examples : ( σ bond)

s-s s-p p-p

(End to end overlap/overlapping along the internuclear axis)

Pi bond ( π bond)

A pi bond is formed by the sidewise overlapping of pure atomic orbitals after the formationof a sigma bond. The extent of overlapping is less, hence a pi bond is weaker than theσ bond.

(Side wise/Lateral Overlapping)

Examples:

a) O2 molecule

The structure of oxygen molecule is O __

__ O

The first line represents a σ bond and the second line represents π bond.

b) N2 molecule : The structure of N2 molecule N ≡ N. The first line represents a σ bondand the second and third lines represent π bonds.

Shapes of Molecules

A theory called VSEPR (Valence Shell Electron Pair Repulsion) helps in explaining theshapes of simple covalent molecules. A bond pair means 2 electrons involved in bonding.A lone pair means a pair of 2 electrons not involved in bonding. They are lonely andsingle. Electron pairs consist of bond pairs & lone pairs. According to this theory, thevarious electron pairs around a central atom orient themselves in such a way that thereis minimum repulsion between them and maximum stability. The decreasing order ofrepulsions among electron pairs is as under

lone pair � lone pair > lone pair � bond pair > bond pair � bond pair

[Whenever there is a lone pair of electrons, there will be distortion in the shape. Theshape will change a little bit.]

www.bmata

lent.c

om

(Free Sam

ple)



Linear MoleculesBeCl

2(Dots represent electrons)

Cl • • Be • • Cl ⇒ Cl�Be�Cl

1 bond pair 1 bond pair

No. of electron pairs = 2

CO2 : O____ C

____ O

HgCl2 : Cl ��Hg��Cl

The angle between Hg and Cl molecules is 1800

Trigonal PlanarThe structure is a triangle.

BF3

Number of bond pairs = 3

TetrahedralCH

4


Trigonal BipyramidalPCl

5


www.bmata

lent.c

om

(Free Sam

ple)



Square Planar[Cu(NH

3)

4]2–


PyramidalNH

3


OctahedralSF

6


[Fe(H2O)

6]+2


www.bmata

lent.c

om

(Free Sam

ple)



Shapes of Molecules and Electron Pairs

No. of e

pairs

Type of

Molecule Shape Bond Angle Examples

2 AB2 Linear 180° BeCl2, CO2

HgCl2, CS2

3 AB3 Planar triangle/

Trigonal planar

120° BF3, BCl3, SO3

4 AB4 Tetrahedral 109°28| CH4, 4NH+

5 AB5 Trigonal

bi- pyramidal

90°, 120° PCl5

6 AB6 Octahedral 90° SF6,

[Fe(H2O)6]2+

L.P. B.P.

2 4

1 3

AB4E2

AB3E

Square planar

Pyramidal

90°

NH3 = 107°

PH3 = 93.3°

[Cu(NH3)4]2+

NH3, PH3

PCl3 L.P. - Lone pair

B.P. - Bond pair

Coordinate covalent bond

It is a special type of covalent bond in which only one of the participating atoms contributesthe electron pair for sharing. The atom which gives the electron pair for sharing iscalled the donor and the other atom which accommodates the shared pair of electrons iscalled an acceptor. In this mechanism, the contribution of electron pair is one�sided,and slight polarity develops in the molecule. A coordinate bond is represented by � → �,pointing from the donor atom to the acceptor atom. A coordinate bond is explainedbelow with the help of some examples.

(a) Formation of HClO :

= =orH + O××

××

×

× H HO××

××

×

× O××

××

×

×Cl Cl Cl

Cl � atom of HClO is the donor and O � atom is the acceptor of a lone pair of electrons.

(b) Formation of NH3 → BF3

H H

H H

H H

+N N• •• •

• •• •

• •

• •

• •

• •

=F F or H � N B � F→

� �

� �

H F

H F

B B

F F

F F

× ×

× ×

× ×

× ×

× ×

× ×

Nitrogen atom of ammonia has a lone pair of electrons and these are accepted by thevacant p orbital of the boron atom of BF3. Hence nitrogen atom is the donor andboron atom is the acceptor.

www.bmata

lent.c

om

(Free Sam

ple)



Metallic bond

Each atom in a metal crystal loses all its valence electrons. The electrons thus obtainedfrom an electron pool. The resulting positively charged metal ions are believed to beheld together by the electron pool. The positively charged metal ions have a definiteposition in the crystal lattice of the metal. The valence electrons are not attached to anyindividual ions, they belong to the crystal as a whole and are free to move throughoutthe metal crystal. The electrostatic force of attraction that binds metal ions to the mobileelectrons within its sphere of influence is known as a metallic bond.

SOLVED EXAMPLES

Example 1:The overlapping orbitals always possess electrons with opposite spin. Give reason.

Solution:

If the overlapping orbitals have electrons with same spin, the increased repulsive forcesbetween the electrons oriented in the same direction increases energy of the systemand decreases stability. Hence overlapping orbitals always need to possess electronswith opposite spin.

Example 2:

Compare the solubilities of various lithium halides in water.

Solution:

Lattice energy of these halides decreases from LiF to LiI with increase in size of theanion. Hydration energy increases from LiF to LiI. The greater difference betweenhydration energy and lattice energy, the greater will be the solubility. Thus LiF is insolubleand LiI is soluble.

Example 3:

Among hybrid orbitals and pure orbitals, which orbitals form stronger bonds ?

Solution:

Hybrid orbitals possess same shape, size and energy. Hence the extent of overlapping ismore in case of hybrid orbital. In hybrid orbital, the electron cloud is concentrated in thelarger lobe which renders larger extent of overlapping and hence results in strongerbond.

Example 4:NF3 and NCl3 have same shape and bond angle. But, NCl3 only undergoes hydrolysis andNF3 does not.

Solution:

In case of NCl3, there are vacant �d� orbitals in chlorine. The lone electron pair of H2Omolecule can be donated to NCl3 as they occupy the vacant d orbitals. Thus, NCl3 undergoeshydrolysis. But, in case of NF3 fluorine has no vacant �d� orbitals. Therefore lone pair ofelectrons in H2O cannot be donated to NF3 molecule. Hence NF3 does not undergohydrolysis.

www.bmata

lent.c

om

(Free Sam

ple)



Ch

em

ical

Bon

din

g

Th

e f

orce

of

att

ract

ion

wh

ich

bin

ds

the a

tom

s to

geth

er

in a

mole

cule

Decr

ease

in

en

erg

y o

f th

e sy

stem

Incr

ease

in

sta

bil

ity o

f th

e s

yst

em

Att

ain

men

t of

octe

t or

du

ple

t co

nfi

gu

rati

onT

ran

sfer

of

ele

ctro

ns

Ele

ctro

vale

ncy

Covale

nt

bon

dC

ovale

ncy

Ion

ic b

on

d

Sh

ari

ng o

f ele

ctro

ns

Ion

ic c

ompou

nds

Pro

pert

ies

Most

ly g

ase

s ra

rely

liqu

ids

or s

oft

soli

ds

Low

melt

ing p

oin

t

Non

-con

du

ctor

Sol

uble

in

non

pola

r

solv

en

ts

Gase

s, l

iqu

ids,

or

soli

ds

Hig

her

m.p

t &

b.p

t

Con

du

ctor

s in

aq.s

olu

tion

Sol

uble

in

pola

rso

lven

t

Covale

nt

com

pou

nd

s

Un

equ

al

shari

ng

Equ

al

shari

ng

Non

pola

r

Pola

r

Coord

inate

covale

nt

bon

d

Bri

ttle

soli

ds

Hig

h m

elt

ing p

oin

ts

Ele

ctri

cal

con

du

ctiv

ity

Sol

ubil

ity i

n p

ola

r so

lven

ts

Str

on

g e

lect

rost

ati

c fo

rce

Non

dir

ect

ion

al

Don

or

Acc

ep

tor

CO

NC

EPT

MA

P www.bmata

lent.c

om

(Free Sam

ple)



Non

bon

ded f

orc

es

of a

ttra

ctio

n

Dip

ole �

dip

ole

att

ract

ion

s

Hyd

rogen

bon

din

gM

eta

llic

bon

d

Non

pola

r co

vale

nt

mole

cule

s or

in

ert

gas

Pola

r co

vale

nt

mole

cule

Hyd

rogen

hig

hly

EN

ato

mM

eta

l io

ns

wit

h

poo

l of

es

�

Very

weak

Sli

gh

tly

stro

nger

Str

on

ger

Str

on

ger

Om

ni

dir

ect

ion

al

Van

derw

aals

forc

es

www.bmata

lent.c

om

(Free Sam

ple)



BASIC PRACTICE

SECTION A

FILL IN THE BLANKS

1. The partial charge separation between the bonded atoms gives rise to ___________.

2. Linear molecules possess ___________ dipole moment.

3. Presence of 3 bond pairs corresponds to ___________ hybridisation.

4. The electron pairs involved in hybridisation and not involved in bonding are called___________.

5. Number of lone pairs and bond pairs in ammonia molecule is ___________.

6. ___________ is the number of electrons contributed for sharing in covalent bondformation.

7. The electrostatic force of attraction that binds metal ions with mobile electronssurrounding within its sphere of influence is called ___________.

8. Helium has ___________ configuration.

9. By losing ___________ electrons, calcium acquires the configuration of ___________.

10. The number of bond pairs in the molecule PCl5 is ___________.

11. Strongest hydrogen bond is present in ___________.

12. ___________ bond is formed between atoms of elements possessing electronegativitiesof 3.5 and 0.8.

13. The greater polarisability of anion gives rise to ___________ character for the bond.

14. ___________ overlapping between orbitals leads to π bond formation.

15. In the formation of water molecule, ___________ number of lone pairs and ___________number of bonds pairs are present.

TRUE OR FALSE

16. All polar covalent compounds possess dipole moment.

17. All homoatomic molecules possess non polar covalent bonds.

18. Metallic bond is non directional.

19. In multiple bonds, all bonds have equal strength.

20. Hydrogen bonding can exist between two molecules or within a single molecule.

21. There are no forces of attraction between the molecules of inert gases.

22. Strength of ionic bond depends on lattice energy.

23. During the bond formation, energy is absorbed.

24. Potential energy curve for covalent bond formation gives bond length.

25. Formation of dative bond involves only transfer of electrons from donor to acceptor.

www.bmata

lent.c

om

(Free Sam

ple)



MATCH THE FOLLOWING

26. Column – I Column – II

A. KCl p. Polar covalent compound

B. NH3 q. sp hybridization in carbon atoms

C. Acetylene r. Dative bond is present

D. H2O s. Pyramidal shape

E. H3O+ ion t. Ionic compound

27. Column – I Column – II

A. Ionic bond p. Water

B. Polar covalent bond q. Calcium chloride

C. Non polar covalent bond r. Ammonium ion

D. Coordinate covalent bond s. Fluorine

E. Hydrogen bonding t. Hydrogen sulphide

FURTHER PRACTICE

MULTIPLE CHOICE QUESTIONS

1. The electronic configuration of an element �A� is [Ne] 3s2 . With which of the followingelements it can form an ionic compound of the type AX2 ?

(A) [He] 2s2 2p2 (B) [Ne] 3s2 3p5 (C) [Ar] 3d10 4s1 (D) [Ne] 3s2 3p4

2. The correct order of strength of bonds is :

(A) s � s > s � p > p � p (B) s � s < s � p < p � p

(C) s � p > s � s > p � p (D) s � s > p � p > s � p

3. Intermolecular forces in solid iodine corresponds to :

(A) covalent bond (B) ionic bond

(C) coordinate covalent bond (D) vanderwaal�s forces

4. When magnesium and oxygen react, energy is :

(A) released, covalent bond is formed (B) absorbed, ionic bond is formed

(C) absorbed, covalent bond is formed (D) released, ionic bond is formed

5. Among the following bonds formed by chlorine atom, the strongest bond is formed withwhich of the following elements ?

(A) Iodine (B) Hydrogen (C) Carbon (D) Chlorine

www.bmata

lent.c

om

(Free Sam

ple)



15. Non directional bond is present in :

(A) KF (B) H2 (C) H2O (D) Both 1 and 2

16. On the basis of which of the following parameters, shape of the molecule can bepredicted ? (only when one parameter is known).

(A) Type of hybridisation (B) Molecular formula

(C) Number of lone pairs and bond pairs (D) Dipole moment

17. When two ice cubes are pressed together, they join together. Identify the type of attraction.Which helps for the above process.

(A) Vanderwaals (B) Covalent bond (C) Dative bond (D) hydrogen bond

18. Identify the correct reason for higher boiling point of ICl than Br2 :

(A) Higher molecular weight of ICl than Br2

(B) Presence of dipole - dipole forces in ICl

(C) Presence of vanderwaals forces in ICl

(D) Presence of vanderwaals forces in ICl

19. Electron pool theory of metals can not explain which of the following characteristics ofmetals ?

(A) Hardness (B) Malleability

(C) Electrical conductivity (D) Sonorousness

20. Which amongst the following is more covalent in nature?

(A) AlF3 (B) AlCl3 (C) CsCl (D) CsF

MULTIPLE ANSWER QUESTIONS

1. Which of the following statements is true regarding 4NH+ ?

(A) 4NH+ contains a dative bond

(B) Bond angle increases when a bond is formed between NH3 and H+.

(C) 4NH+ has pyramidal shape.

(D) The type of hybridisation changes when a bond is formed between NH3 and H+

2. Identify the correct reason for zero dipole moment.

(A) The molecule may be homoatomic

(B) There may be a dative bond in the molecule

(C) The molecule may be heteroatomic and symmetric

(D) There may be lone pairs in the molecule

3. Which of the following molecules possess same shape as H3O+ ?

(A) 4NH+ (B) NH3 (C) PH3 (D) CH4

www.bmata

lent.c

om

(Free Sam

ple)



4. Identify the correct order of lattice energies :

(A) CsCl < RbCl < KCl < NaCl (B) KCl > CaCl2 > AlCl3

(C) NaCl < LiCl < MgCl2 < AlCl3 (D) LiCl > NaCl < MgCl2 < AlCl3

5. Identify the consequences of hydrogen bonding :

(A) Solubility of an ionic compound in water

(B) Solubility of a covalent compound in water

(C) Existence in liquid state

(D) Low boiling points

6. Which of the following electronic configurations are associated with the formation ofmolecule with expanded octet ?

(A) [He] 2s2 2p1 (B) [He] 2s2 2p2 (C) [Ne] 3s2 3p3 (D) [Ne] 3s2 3p4

7. Among the following identify the molecules with sp2 - p σ bonds.

(A) BeCl2 (B) C2H2 (C) BCl3 (D) BF3

ASSERTION AND REASON TYPE QUESTIONS

The questions given below consist of statements of an Assertion and a Reason. Use thefollowing key to choose the appropriate answer.

(A) If both assertion and reason are CORRECT and reason is the CORRECT explanationof the assertion.

(B) If both assertion and reason are CORRECT, but reason is NOT THE CORRECTexplanation of the assertion.

(C) If assertion is CORRECT, but reason is INCORRECT.

(D) If assertion is INCORRECT, but reason is CORRECT.

(E) If both assertion and reason are INCORRECT.

1. Assertion : Malleability of a metal is due to the presence of metallic bond.

Reason : Metallic bond is non directional

2. Assertion : There is a carbon carbon double bond in ethylene molecule

Reason : Hybrid orbitals can form both sigma and pi bonds

3. Assertion : Water molecule is linear in shape

Reason : There are two lone pairs and two bond pairs in water molecule

4. Assertion : Two chlorine atoms are bound by a single bond

Reason : There is only one unpaired electron in the valence shell of chlorine

5. Assertion : Sigma bond is stronger than pi bond

Reason : The strength of a bond depends on the extent of overlap

6. Assertion : CCl4 has zero dipole moment whereas CHCl3 has dipole moment

Reason : Dipole moment is a vector quantity

www.bmata

lent.c

om

(Free Sam

ple)



7. Assertion : LiF has more covalent character than CsF

Reason : Lattice energy of CsF is less than that of LiF

8. Assertion : PCl5 is an unstable molecule

Reason : Formation of PCl5 does not follow octet tule

9. Assertion : Glucose is soluble in water

Reason : There is hydrogen bonding in water

10.Assertion : CO2 molecule is linear in shape

Reason : Any atom bonded to two other atoms should be linear

PARAGRAPH QUESTIONS

Passage - I

Coordinate covalent bond is a special type of covalent bond in which only one of thebonded atoms contributes the electron pair for sharing.

i) In ammonium ion, identify donor and acceptor.

(A) ammonia, hydrogen chloride

(B) hydrogen ion, ammonium hydroxide

(C) ammonia, hydrogen ion

(D) ammonium hydroxide, hydrogen chloride

ii) Identify the number of lone pairs donated by donor in the formation of ammoniaboron trifluoride?

(A) 1 (B) 2 (C) 3 (D) 4

iii) Depict the formation of ammonium ion by Lewis dot structure.

(A)

H

H

H

N• •

• •

••

••

FB

F

F

×

×

×

×

×

×

(B)

H

H

H

N• •

• •

••

••

H+

(C)

H

H

N• •

••

•• H

+

(D)

H

H

H

N• •

•

• •

•

••

••

H

iv) How is coordinate covalent bond denoted ? What is the other name for it ?

(A) arrow, dative bond

(B) dots, dative bond

(C) arrow, covalency

(D) dots, hydrogen bond

v) Give another example for the formation of the above type of bond.

(A) hydronium ion (B) sulphur dioxide

(C) water (D) ammonia

www.bmata

lent.c

om

(Free Sam

ple)



SECTION – B

CONCEPTUAL QUESTIONS

1. Between two similar or dissimilar atoms, one sigma bond only is possible whereas two pibonds can be formed explain.

2. Explain the formation of H3O+ ion. Give its shape and bond angle with proper justification.

3. The formation of 4 bonds in methane can be explained by considering the excited stateconfiguration of carbon. Then, what is the need for the concept of hybridisation ?

4. When sufficient force is applied, ionic crystals and covalent solids also break. But, metalscan be made into thin sheets or foils by the application of same amount of force. Givereason.

5. Rules of hybridisation say that hybrid orbitals form only sigma bonds. However,unsaturated hydrocarbons like (ethylene and acetylene) possess multiple bonds betweencarbons.

6. Lone pairs and bond pairs possess electrons. However, the repulsion experienced bylone pairs is much greater than that experienced by bond pairs. What reason can beattributed to this ?

7. Explain the shapes of AX3 type molecules without any lone pairs, with one lone pair andwith two lone pairs.

8. Fluorine has lesser electron affinity value than chlorine. However, fluorine shows greater

ease of formation of F� ion than chlorine for Cl− ion. How do you justify this ?

9. Melting point of MgCl2 is greater than that of BaCl2. Give reason ?

10. Phosphorous can form two types of halides whereas nitrogen can form only one type ofhalide. Give reason.

SECTION – C

PREVIOUS CONTEST QUESTIONS

1. The hybridisation of carbon atoms in C � C single bond of 2HC C CH CH≡ − = is :

(A) sp3 � sp3 (B) sp2 � sp3 (C) sp � sp2 (D) sp3 � sp

2. The correct order of bond angles in H2S, NH3, BF3 and SiH4 :

(A) H2S < SiH4 < NH3 < BF3 (B) NH3 < H2S < SiH4 < BF3

(C) H2S < NH3 < SiH4 < BF3 (D) H2S < NH3 < BF3 < SiH4

3. The molecule having zero dipole moment is :

(A) CHCl3 (B) H2O (C) CCl4 (D) HCl

4. The number of sigma bonds in ethane formed by the overlap of sp3 and s orbitals is :

(A) 5 (B) 6 (C) 7 (D) 4

www.bmata

lent.c

om

(Free Sam

ple)



5. Which one of the following statements is true for ammonium ion ?

(A) All bonds are ionic.

(B) All bonds are dative bonds.

(C) Hydrogen atoms are situated at the corners of a tetrahedron.

(D) None

6. According to VSEPR theory, the shape of AB3 type of molecule in which the central atomhas one lone pair of electrons :

(A) pyramidal (B) tetrahedral (C) trigonal planar (D) linear

7. In which of the following is the hydrogen bonding strongest in gas phase ?

(A) HF (B) CH4 (C) HI (D) PH3

8. In which of the following substances highest covalent character is found ?

(A) CaF2 (B) CaCl2 (C) CaBr2 (D) CaI2

9. The bonds present in K4[Fe(CN)6] are :

(A) all ionic

(B) all covalent

(C) ionic and covalent

(D) ionic, covalent and coordinate covalent bonds

10. The ion which is isoelectronic with CO is :

(A) CN� (B) 2O− (C) 2N+ (D) 2O+

11. BCl3 molecule is planar while NCl3 is pyramidal because :

(A) BCl3 does not have lone pair on B but NCl3 has one lone pair on N.

(B) B � Cl bond is more polar than N � Cl bond.

(C) N atom is smaller than B.

(D) N � Cl bond is more covalent than B � Cl bond.

12. Which one among the following is not paramagnetic ?

(A) Be� (B) Ne2+ (C) Cl� (D) As+

13. According to Fajan�s rule, covalent bond is favoured by :

(A) large cation and small anion (B) large cation and large anion

(C) small cation and small anion (D) small cation and large anion

14. The bond length between C � C bonds in sp2 hybridised atom is :

(A) 1 : 2 A°

(B) 1.32 A°

(C) 1.54 A°

(D) 1.4 A°

15. The hybridisation of sulphur in SO2 is :

(A) sp2 (B) sp3 (C) spd3 (D) sd3

www.bmata

lent.c

om

(Free Sam

ple)



BRAIN NURTURES

1. Sodium has lower IP value and hence is highly metallic in nature. But, it is so soft thatit can be cut with knife. Iron is a hard metal though its ionisation potential value ishigher than that of sodium. Justify.

2. A molecule HX can form stronger hydrogen bond than another molecule HsY. But HXboils at a lower temperature than H2Y. Identify HX and H2Y and give reason for thepeculiar behaviour.

3.

Internuclear distance

Is the above energy profile diagram the formation of hydrogen molecule correct in allrespects ? If not explain and draw the correct figure.

4. Consider isoelectronic series of A+, B+2, C+3. Compare the relative covalent characters oftheir chlorides. Give justification.

5. Had repulsions between the different types of electron pairs been equal, what wouldhave been the shapes of H2O and NH3 molecules.

6. The valencies of p block elements are equal to group number or 8 - group number.Therefore they show one lower valency and one higher valency. However, if we go tothe bottom elements of any group, the compounds with lower valency are predominantwhereas higher valency becomes rather uncommon. Explain.

7. Among metals of its own group, only mercury is a liquid. Give reason.

8. When water and mercury are spilled on floor, what difference do you observe in theirbehaviour or appearance ? Justify.

9. An atom �X� has 5 electrons in �M� shell. It can form XCl5 and XCl3. Explain their formation.

10. Two elements X and Y have L and M as valence shells and can form stable di negativeions. But, they also form covalent compounds with hydrogen. One is a gas (compoundwith Y) and one is a liquid (compound with X) at room temperature. Identify X and Y andthe compounds. Give reason for their respective physical states.

11. Electronegativity value of 2nd period, VA group element is same as that of 3rd period, VIIA group element. But, the hydride of former can go into liquid state more easily than thehydride of latter. Justify.

www.bmata

lent.c

om

(Free Sam

ple)



Crossword Puzzle

1 2 3

4

5

6

7

ACROSS

1 This property is seen in water molecule.

5 Inert gases (except helium) have thisconfiguration in outer shells.

7 Energy released when oppositely charge ions arebrought together.

DOWN

1 Ammonium ions have this type of bond.

2 Metal atoms are united together by this

3 Shape of methane molecule

4 Hydrogen fluoride molecules have this type ofbond

5 Hybridisation takes place among these to levelthe energy differences.

6 Most of the ionic compounds exist in this physicalstate

www.bmata

lent.c

om

(Free Sam

ple)

` 75Detailed solutionsfor all problems

of IIT Foundation &Olympiad Explorer

are available in this book

CLASS - XSolutions

CLASS - X

FOUNDATION OLYMPIAD&

IIT F

oundatio

n &

Olym

pia

d E

xplo

rer - C

hem

istry Cla

ss - X

CH

EM

IS

TR

Y

IntegratedSyllabus

CH

EM

IS

TR

Y

UNIQUE ATTRACTIONS

�

� Cross word Puzzles

� Graded Exercise

Basic Practice�

Further Practice�

Brain Nurtures�

� Numerical Problems

Conceptual Questions

� Multiple Answer Questions

� Paragraph Questions

� Assertion & Reason TypeQuestions

YOUR

COACH

India’s FIRST scientifically designed portalfor Olympiad preparation• Olympiad & Talent Exams preparation packages

Analysis Reports Previous question papers• •Free Demo Packages Free Android Mobile App• •

Get 15% discount on all packages by using the discount coupon code: KR157N

A unique opportunity to take about 50 tests per subject.

` 200

www.bmata

lent.c

om

(Free Sam

ple)

integrated syllabus foundation olympiad& www ......`75 detailed solutions for all problems of...

Documents