CLASS 10th CHEMISTRY NOTES CHAPTER 11 ORGANIC CHEMISTRY

Table of Contents

CLASS 10th CHEMISTRY NOTES CHAPTER 11 ORGANIC CHEMISTRY

CLASS 10th CHEMISTRY NOTES CHAPTER 11 ORGANIC CHEMISTRY. Organic chemistry is a branch of chemistry that studies the structure, properties and reactions of organic compounds, which contain carbon in covalent bonds. The study of the structure determines its structural formula. The study of properties includes the physical and chemical properties and the evaluation of chemical reactivity to understand their behavior.CLASS 10th CHEMISTRY NOTES CHAPTER 11 ORGANIC CHEMISTRY. The study of organic reactions includes the chemical synthesis of natural products, drugs and polymers, and the study of individual organic molecules in the laboratory and through theoretical study.CLASS 10th CHEMISTRY NOTES CHAPTER 11 ORGANIC CHEMISTRY.

CLASS 10th CHEMISTRY NOTES CHAPTER 11 ORGANIC CHEMISTRY

CLASS 10th CHEMISTRY NOTES CHAPTER 11 ORGANIC CHEMISTRY
CLASS 10th CHEMISTRY NOTES CHAPTER 11 ORGANIC CHEMISTRY

CLASS 10th CHEMISTRY NOTES CHAPTER 11 ORGANIC CHEMISTRY

CLASS 10th CHEMISTRY NOTES CHAPTER 11 ORGANIC CHEMISTRY. The range of chemicals studied in organic chemistry includes hydrocarbons as well as carbon-based compounds, but also containing other elements, especially oxygen, nitrogen, sulfur, phosphorus and halogens. Nonmetallic chemistry is the study of compounds that contain carbon-metal bonds.CLASS 10th CHEMISTRY NOTES CHAPTER 11 ORGANIC CHEMISTRY.

CLASS 10th CHEMISTRY NOTES CHAPTER 11 ORGANIC CHEMISTRY

CLASS 10th CHEMISTRY NOTES CHAPTER 11 ORGANIC CHEMISTRY
CLASS 10th CHEMISTRY NOTES CHAPTER 11 ORGANIC CHEMISTRY

CLASS 10th CHEMISTRY NOTES CHAPTER 11 ORGANIC CHEMISTRY

CLASS 10th CHEMISTRY NOTES CHAPTER 11 ORGANIC CHEMISTRY. Additionally, contemporary research is focused on organic chemistry involving other nonmetallic, including landslides, but especially the transition metals zinc, copper, palladium, nickel, cobalt, titanium, and chromium.CLASS 10th CHEMISTRY NOTES CHAPTER 11 ORGANIC CHEMISTRY.

CLASS 10th CHEMISTRY NOTES CHAPTER 11 ORGANIC CHEMISTRY

Chapter No.11

word image 28

Q.1 What is vital force theory?

Ans. Vita’ force theory:

Vital theory was presented by a Swedish Chemist, Berzelius in 1815. According to this theory organic compounds cannot be prepared in laboratory. They are only prepared in the bodies of living organisms under the influence of a supernatural force called vital force.

For example:

Urea (from urine), tartaric acid (from grapes); citric acid (from-lemon) and sucrose (from cane sugar) are organic compounds.

Rejection of vital force theory:

In 1828, a German chemist Friedrich Wohler prepared an organic compound (urea) in the laboratory by heating ammonium connate and rejected the vital force theory. Ammonium connate is obtained by heating solid ammonium chloride with solid potassium connate.

NH4CI (s) + KCNO, $) • “r”` >NH4CNO (s) + KCI(s) NH4CNO HZNCONH2 (urea)

Q.2 Why organic compounds are peace in a separate branch of chemistry?

Ans. Reason biasing organic compounds in separate branch of

Chemistry:

The organic compounds have common properties and .they is very large in number. – Thus, to make their study easier they are placed in a separate branch of chemistry caned organic chemistry.

Q.3 Which compounds of carbon are not organic?

Ans: The following compounds of carbon are not included in organic Compounds because they do not possess the properties of organic.

i. Carbonates like sodium• carbonate, potassium carbonate calcium carbonate -to

ii. Bicarbonates: like sodium bicarbonate, magnesium bicarbonate, calcium bicarbonate.etc.

iii. Cyanides: like potassium cyanide, sodium cyanide, magnesium cyanide etc.

iv. Carbides like calcium carbide, aluminum carbide etc.

v. Carbon monoxide:(CO)

vi. Carbon dioxide: CO2

vii. Sulphide: like carbon sulphide

Q.4. Define organic compounds and organic chemistry?

Ans. Organic compounds:

“The compounds of carbon and hydrogen called hydrocarbons. Hydrocarbons and their derivatives are called organic compounds.” Composition of organic compounds:

All organic compounds contain carbon and hydrogen as an essential ingredient beside these elements they may also contain halogens, sulphur, oxygen, nitrogen.

Derivatives of hydrocarbon:

When hydrogen atom of hydrocarbon is replaced by an atom or group of atoms then the resulting compound will be the derivative of that hydrocarbon.

For example:

If we remove one H from ethane C2H6 then ethyl group(C2H5) is obtained thus ethyl alcohol(C2H5OH), ethyl chloride(C2H5CI), ethyl bromide(C2H5Br) are the examples of derivatives of ethane.

Organic chemistry:

“The branch of chemistry which deals with the study of hydrocarbons and their derivatives is called organic chemistry.” For example, in this branch we study about alkanes like methane, alcohols like ethyl alcohol etc.

Q.5: How organic compounds are represented by

1. Molecular formula

2. Structural formula

3. Condensed formula

4. Dot and cross formula Ans.1.Molecular Formula:

“Molecular formula shows the actual number of atoms in a molecule of organic compound

Example:

Compound Name

Molecular Formula

Methane

CH4

Benzene

C6H6

Propane

C 3H 8

Butane

C4 H10

2. Structural Formula:

This formula represents the arrangement of different atoms of various elements around the carbon atoms present in a molecule of a compound.”

Explanation:

Structural formula shows the nature and type of atoms present in a molecule of a compound. It also shows the bonding arrangement of atoms.

In structural formula, single bonds are shown by single dash (—), double bond by double dashes (–_–) and triple bond by triple dashes ( between the bonded atoms.

Examples:

Structural formulas of some compounds are given below:

H, H H H

I I I I

H— c—H H— C—C —H H—C —C— C—H

I

H H H H H H

(Methane) (Ethane) (Propane)

3. Condensed Formula:

In this formula group of atoms are shown in an order with no bonds or dashes.

Examples:

i. For example hexane (C6H14) has the condensed formula ofc1-13(cl-2)4cH3. Ii.They condensed formula of heptane (C7H15) is CH3 (CH2)5CH3

4. Dot and Cross Formula I Electronic formula: The type of formula in which electrons are represented in the form of dots and cross of an organic compound is called Dot and cross formula. e.g.

Hx C x H H.0 CxH

X X

H

CH4 C2H6

Table: Name, molecular formula, condensed formula and structural formula of first ten Hydrocarbons.

S.

No

1

Name

Methane

General Formula

C n H2n.2

C 1 H 2x1.2

Molecular Formula

CH4

Condensed Formula

CH,

Structural Formula

H

H- 9 —f,
H

2

Ethane

C 2 H 2×2.2

C2H6

H:JCCH3

H H

I

II —C—H

I 1

H H

3

Propane

C 3H 2×3.2

C3H8

f*CCH2CH3

H H H

I 1 !
H—CC -C-171
1 I I
H H H

4

Butane

C4 H2x4+2

C4H10

H 3C(CH2),C H3

HHHH
1 1 1 1
H—C—C—C—C—H
1 1 1 1
HHHH

5

Pentane

C5H .1×5.2

C 5 H ‘2

H ,C(CH2),CH-,

H H H H H

I il li
HCCCCCH

HHHHH

6

Hexane

C6H2x6+2

C e H ,4

H ,C(CHO4CH3

HHHHHH

111111

HCCCCCCH

111111

H H . H P H H

7

Heptane

C7H2.7.2

C >1-1-,

H,C(CH.::■,,CH

I ! 1 , ill

T?CCC.-CC

H H H 4 4 4 k4

8

Octane

C 8 H 2×8.2

C8 H is

I I

! . ..-.

H iC(CHS),CH-: “—(. —,, __–, –II

1 II ;I ” , ” ‘I

9

Nonage

C 9 H 2×9.2

C9H2,-,

H H 11 .1, H H H H H

Fi,c(cH2),CHJ ,.—-;-..-,,—,7-,.—,,.-<,H.-.-“

10

Deane

C,9/1200-2

Ci0H 22

H,C(CH2),CH3

, .7 ,` ”, ‘,’ ” ,

•’; ” `

.,-c.7—-7—-.i..—-

X IX H Ft • H H H H x H

6: Describe the classification of organic compounds. Ans. Classification of Organic Compounds:

The classification of organic compounds’ given below:

On the basis of carbon skeleton

2, On the basis of bonds

The detail is given below:

1. On the basis of carbon skeleton:

On the basis of carbon skeleton, organic compounds have the following two types:

i. Open chain organic compounds

ii. Close chain or cyclic organic compounds

i. Open chain organic compounds:

“The types of organic compounds which consist of open chain of carbon atoms are called open chain organic compounds or aliphatic organic compounds.”

Open chain organic compounds are further classified into two types which are given below:

a. Straight chain organic compounds:

“The types of open chain organic compounds which contain straight chain of carbon in their molecules are called straight chain organic compounds.”

A carbon atom in straight chain organic compounds is not directly bonded to more than two carbon atoms. The prefix n is put before their names which mean “normal.”

Examples:

Some examples of straight chain organic compounds are given below: CH3—CH2T—CH2—CH3 (n-butane)

ii. CH3—CH,-012—CH,—C113 (n-pentane)

iii. CH,—CH,–CH, —CH,—CH,—CH3 (n-hexane)

b. Branched chain organic compounds:

The type of open chain organic compounds which contains branches of carbon atoms is called branched chain organic compounds.”

At least one carbon atom in their molecules is directly bonded to more than two carbon atoms. Their common names have prefix iso- with corresponding organic compound.

Examples:

Some examples of branched chain alkanes are given below: CH3 —C H-0-13 CH3—CH2—CH—CH3

CH3 CH3

(Iso-butane) (Is-pentane)

CI-1,

I H—

CH3

Eso-hexane)

ii. Close chain or cyclic organic compounds:

The type of organic compound in which the carbon atoms are linked in cyclic form or ring form is called cyclic organic compound.”

For cyclic form at least three carbons must be present.

These are further classified into two types:

a. Hemicyclic or carbocyclic organic compounds

b. Heterocyclic organic compounds

a. Hemicyclic or carboxylic organic compounds:

The type of cyclic organic compounds in which the ring is composed of carbon atoms only is called hemicyclic or carboxylic organic compounds.

These have further two types:

i. Ali-cyclic organic compounds

ii. Aromatic organic compounds

i. Ali-cyclic organic compounds;

These are the type of hemicyclic organic compounds in which the carbon ring do not have alternate double and single bonds(aromatic character). They resemble the open chain organic compounds in their properties but differ from them in their formula. They differ from their corresponding open chain member by H2 group.

Examples:

Examples of Ali-cyclic organic compounds are given below:

CH2

H2C CH2 H2C

CH2

Cycle-propane Cycle-butane

FIX

H2C CH,

CH2

Cycle-hexane

ii. Aromatic organic compounds:

These are the type of hemicyclic organic compounds in which the carbon rings have alternate double and single bonds. The important member of this class is benzene and the compounds derived from benzene.

Examples:

Some examples of aromatic organic compounds are given below:

CH3

Benzene Toluene

Indene Naphthalene

Anthracite

b. Heterocyclic organic compounds:

The type of cyclic organic compounds in which the ring contain other atoms like nitrogen, sulphur etc. along with carbon are called heterocyclic organic compounds.

Examples:

Furan Theophany

Parole

Pyridine

2. On the basis of bonds:

On the basis of bonds there are two types of organic compounds:

i. Saturated organic compounds

ii. Unsaturated organic compounds

Their detail is given below:

I. Saturated organic compounds:

“The organic compounds which contain all carbon-carbon single bonds are called saturated organic compounds.”

In case of hydrocarbons saturated hydro-carbons are called alkanes. Examples:

Methane (CH4), Ethane (C2H6), propane (C3H8) and butane (C4Hio) etc. are the examples of saturated organic compounds.

Unsaturated organic compounds:

The organic compounds containing at least one carbon-carbon double or triple bond are called unsaturated organic compounds.” Examples:

Ethene (C2H4), propene (C3H6). Butane (C4H8) etc. are the examples of unsaturated organic compounds.

ORGANIC COMPOUNDS:

Open chain hydrocarbons) Closed chain or Cycle hydrocarbons

‘Saturated Hydrocarbons jAlkanes) e.q:

Methane: ethane,’ Unsaturated Hydrocarbons, 1Hornocyclic

[Hydrocarbons, (Heterocyclic Hydrocarbons e.g.: Pyridine

rAlkenes (C=C)l Alkynes (C.C) e.g.: Ethane ,e.g.- Ethyne Ait cyclic )r.”-Aomatic

E.g. Cvclo orocane: e.g.: benzene Sat.,..•3tez Linsat. Zatec

I Cycloalkanes C cloalkenes [Cycloalkanes

.7. Explain diversity and magnitude of organic compounds? s. Diversity and magnitude of organic compounds:

The diversity and magnitude of organic compounds is due to the unique structure and bonding of carbon. Due to unique bonding, carbon forms a variety of structures including chains and rings of many shapes and sizes. Some of the main reasons of diversity and magnitude of organic compounds is given below:

1. Tetra-valet:

Carbon is tetra-valet in nature because it has four electrons in its valance shell and requires four more electrons to complete its octet

2. Mode of bonding:

Carbon can form single double or triple bonds in organic compound in different ways given below:

-C- C= C-7—=

Two single and one Two double One triple bond &

Four single Bonds double bond bonds one single bond

3. Carbon-carbon bonding (Catenation):

Carbon atom form bonds with other carbon atoms in different ways to form straight chain, branched chain and rings. This ability of carbon, to bond with other carbon atoms in different ways, is called catenation.

1 1 I I 1

—C—C—C—C—C— Straight chain

1 1 I I 1

I I I I

—C—C—C—C— branched chain

1 1 1 1

—C-

1

1 1

—C—C— closed chain

1 I (Ring)

1 1

4. Carbon bonding with other elements:

Carbon atom can also bond with other elements like oxygen, nitrogen, sulphur to form different organic compounds. Example; H

5. Different arrangement of same atoms (isomerism);

Due different arrangements of same atoms there are a large number of organic compounds. These compounds which have same atoms but different arrangement have different properties.

Example:

For example the molecular formula C2H60 represents both ethanol and di-methyl ether.

CH3-O-CH3 CH3-CH2-OH

Di-methyl ether Ethanol

6. Strength of covalent bonds of C-atoms:

A large number of organic compounds are also available due strong covalent bonding of carbon between themselves and other elements like sulphur, nitrogen, oxygen etc.

Q: Give characteristic properties of organic compounds.

Ans. Characteristic properties of organic compounds:

Organic compounds have the following general properties:

I. Origin:

The main source of organic compounds is plants and animals.

  1. Composition:

Carbon is an essential component of all organic compounds.

However beside carbon they also contain hydrogen as essential part. They may also contain some other elements like sulphur, nitrogen, oxygen and halogen.

  1. Thermal Instability:

Many organic compounds are thermally unstable and decompose to simple substances on heating.

  1. Low melting points and boiling points:

Organic compounds have generally low melting points and boiling points and they are generally volatile due to weak intermolecular force.

  1. Bonding:

Organic compounds are generally covalent in nature in which most are

Non-polar.

  1. Soluble

As most of the organic compounds are non-polar therefore, they are soluble in non-polar solvent like benzene, acetone, and ether and less soluble or insoluble in polar solvents like water.

  1. Electrical conductivity:

Most of the covalent compounds are non-polar therefore, poor conductors of electricity in molten or solution form.

  1. Inflammability:

Most of the organic compounds are inflammable. They burn out to give carbon dioxide, water vapors and energy.

  1. Reactivity the reactions of organic compounds are much slower than the inorganic compounds.
  2. Isomerism:

The compounds having same molecular formula but different structures are called isomers and this phenomenon is called isomerism. Isomerism is common in most organic compounds. For example butane has two isomers n-butane and iso-butane both have the molecular formula C4Filo but they have different structures.

Similarity in behavior:

Different organic compounds show similar behavior due to the presence of same functional group.

9. Describe the sources of organic compounds.

Ans. Sources of organic compounds:

Sources of organic compounds may be natural or they may be prepared synthetically.

Natural sources of organic compounds:

-N-ataraimirgarlic compounds formed by plants and animals are Coal, petroleum and natural gas. These are the main sources of large variety of organic compounds and are called fossil fuels.

Formation of fossil fuels:

Coal, petroleum Ana natural gas are called fossil fuels because they are formed from the decay of plants and animals buried under ground. After a long period of time the plants and animals were changed to fossil fuels.

The detail of natural sources is given below:

i. Coal:

“A combustible organic rock composed primarily of carbon, hydrogen, and oxygen is called coal.”

Composition of coal:

Coal consists mainly of hydrocarbons. In addition to hydrocarbons coal also contains organic compounds containing nitrogen, oxygen and Sulphur. Coal also contains inorganic components, known as ash. Destructive distillation of coal:

When coal is heated in the absence of air, this process is called destructive distillation or carbonization of coal.

Products obtained by destructive distillation of coal:

Coal yields coke, ammoniac liquor, coal gas and coal tar at high temperature in the absence of air. More than 200 organic compounds have been isolated from coal tar.

Uses:

Coal is a major source of organic compounds. It is used as a solid fuel.

. Petroleum (Petra = rock, ileum = oil):

Petroleum is also an important source of organic compounds. It may be defined as follows:

“A dark brown coloured and unpleasing smelling liquid that consists of mixture of various hydrocarbons, found in sedimentary rock of earth is called petroleum.”

It is also called rock oil, crude oil, liquid gold and mineral oil. Composition of petroleum:

Petroleum consists of hydrocarbons majority of which are open and cyclic alkanes.

Fractional distillation of petroleum:

By fractional distillation of petroleum many useful products are obtained. These are petroleum gases, petrol and naphtha, kerosene, diesel oil, lubricating oil and bitumen.

Uses:

After refining. Petroleum is used as a fuel in the form of petrol, diesel, kerosene etc. It is also used for the production of useful products like synthetic rubber, plastics and explosives etc.

iii. Natural gas:

It is also a natural source of organic compounds. It may be defined as;

“A flammable gaseous mixture consisting of hydrocarbons found naturally inside earth is known as natural gas.”

It is usually found together with petroleum.

Composition:

Natural gas consists of 85% methane and 15% ethane, propane and butane. It may also contain small amounts of hydrogen sulphide (H2S), nitrogen (N2) and (CO2) which are often removed during refining process. Uses:

Natural gas is used as fuel for domestic as well as industrial purposes. It is also used for the production of many organic compounds like methyl alcohol etc. It is a chief source of power generation in Pakistan.

iv. Plants:

Plants are also source of organic compounds. They produce carbohydrates, proteins, vitamins, oils etc. Most of the organic compounds are obtained directly from plants. E.g. sugar while some other are indirectly obtained from their decay and death.

v. Animals:

A variety of organic compounds like protein are obtained from animals in the form of meat, mutton, chicken, egg etc.

Q: Explain the synthesis of organic compounds in the laboratory?

Ans. Synthetic of organic compounds in laboratory:

Organic compounds are also prepared in laboratory and industries. In earlier times it was thought that organic compounds cannot be prepared in laboratory (Vital force theory) but after the synthesis of urea (H2NCONH2) this theory was rejected and a large number of organic compounds were prepared in the laboratory and industries.

In 1828, a German chemist Friedrich Wohler prepared an organic compound (urea) in the laboratory by heating ammonium connate. Ammonium connate is obtained by heating solid ammonium chloride with solid potassium connate.

NH4CI (s) + KCNO (s) He’ NH4CNO (s) + KCI(s)

NH4CNO (s) H2NCONH2 (urea)

Q.11. Describe the uses of organic compounds.

Ans. Uses of organic compounds:

The uses of organic compounds are given below:

I. In medicines:

Many organic compounds are used in medicines.

Ii. In food:

The foods we eat contain many organic compounds like carbohydrates, proteins and vitamins etc.

Iii. In power generation:

Mixture of organic compounds like natural gas, petrol and diesel are used in power generation.

iv. As fuels:

Mixtures of organic compounds like natural gas. Petrol. Kerosene and diesel etc. are used as fuels. They are the main sources of energy for human beings.

Vi. In industries:

Organic compounds are also used in industries:

Vii. As life molecules:

The four C-C. — 0=’, D0 cells and their par `s —hese of..- ”pads and. Nucleic acids. These are called life molecules.

Viii. As clothing:

Cloths are made of fibers. These fibers may be natural or synthetic and these are organic compounds.

Q.12. what are alkanes?

Ans. Alkanes:

Example:

 

I

J. IIV 111dIIIV VI dIRd1140 kolIe1111U:11 IVIIIII.JItIkVnr12n+21

1

1 Methane CH4

 

2

2 1 Ethane C2H6

 

3

3. l 1 Propane C3H8

 

4

4 1 Butane C4H10

 

5

5 : Pentane C.51-112

6 Hexane . .

 

6

14

 

7

Heptane

 

8

Octane

 

9

Nonage

 

10

  

Q.13: How alkanes are name? Or ascribe the rules?

Ans. Naming of alkanes (nomenclature):

“The naming of alkanes under certain rules is called nomenclature.” Rules for naming alkanes (straight chain):

Simple straight chain alkanes can be named by the following rules:

i. Count the number of carbon atoms in the formula of alkanes.

Ii.Give prefixes meth for 1, eth for 2, prop for 3, but for 4 carbon atoms

Respectively etc.

iii. Add suffix -ana to the corresponding prefix. Thus the full name of simple straight chain alkane is obtained.

Examples:

(CnH2n+2) C-atoms (Prefixes) .

t..nemical rormula 1 Numoer or k.vreeK numerals • run name

 

CH4 1 Meth- Methane

  

C2H6 2 Eth- Ethane

  
 

C3H8 ‘3 Prop- Propane

  
 

C4H10 4 But- Butane

  
 

C5H12 5 ‘ Pent- Pentane

  
 

C6H14 6 Hex- Hexane

  
 

C7H16 7 Hept- Heptane

  
 

08H18 8 j Oct- Octane

  
 

C9H2o 9 I Non- Nonane

  
 

C10H22 10 I Dec- Decane

  

14. What is homologous series? Give the names of alkane homologous series up to ten C-atoms.

Ans. Homologous series :( Homo = same, logos = properties)

“A series of organic compounds having same chemical properties but each member differ from the adjacent member by methylene group (-CH2-) is called homologous series while each member of homologous series is called homologue. “OR

“A series of organic compounds having same elements with same general formula and same chemical properties but each member differ from adjacent member by methylene group (-CH2-) is called homologous series while each member of homologous series is called homologue.”

Properties of homologous series:

i. They have the same general formula.

ii. They have the same functional group.

Ii. They have the same chemical properties.

Ii. They have different physical properties.

v. Each member of homologous series differs from adjacent member by -CH2- group.

vi. They have the same general methods of preparations.

Examples:

There are seven homologous series of the organic compounds they are hydrocarbons, alcohols, carboxylic acids, carbonyl compounds (aldehydes and ketones), ethers, amines and alkyl halides.

Homologous series of alkanes:

Alkanes are saturated hydrocarbons having general formula of CnH2n+2 where n is the number of carbon atoms. Names and formulas of first ten alkanes are given in the table below:

C-atoms Name of alkane

 

Chemical formula

(CnH2n..2)

1

Methane

 

‘ CH4

2

Ethane

 

C2H6

3

Propane

 

C3H8

4

Butane

 

C4Fl10

5 Pentane

 

C5H12

6

Hexane

 

C6H14

7

Heptane

 

C7F116

8

Octane

i

C8H18

9

Nonage

,

 

C91120

10

Deane

khan

l0 22

Activity:

What is the next homologue of each the following compounds?

C3H8

ii. CH3OH

iii.CH3000H

iv. C2H5Br

v. C3H7NH2

Ans: Given compound:

Next homologue:

C3H8 (Propane)

C4H» (Butane)

CH3OH (Methyl alcohol) C2H5OH (Ethyl alcohol) CH3C00H (Ethanoic acid) C2H8C00H (Propionic acid) C2H5Br (Ethyl bromide) C3H7Br (Propyl bromide)

v. Given compound: C3H7NH2 (Propyl amine)

Ans: Next homologue: C4H9NH2 (Butyl amine)

15. Write a note on cycloalkanes?

Ans. Cycloalkanes:

“Cycloalkanes are the alkanes in which carbons atoms are arranged in a ring or cyclic structure with no alternate double and single bonds.”

Characteristics:

i. They have no free carbon atom end.(primary carbon)

ii. They have two hydrogen less than the corresponding straight chair alkanes.

iii. They have the general formula of CnH2n.

Example:

CH2

H2C

 

CH2

 

H2C CH2

H2C

 

CH2

Cacao-propane CH2 Cycle-butane

H2C

 

CH,

HZC

 

CH2

CH2

Cyclo-hexane

Q.16. what are alkyl radicals? Explain with examples.

Alkyl radical/group:

“A radical or group of atoms obtained by removing one hydrogen atom from an alkane is called alkyl group.”

General formula:

The general formula of alkyl radical is CnH2n,i. where n is the number of carbon atoms i.e. 1,2,3,4 etc.

General Symbol:

Alkyl radicals are denoted by a general symbol —R.

Naming an alkyl radical:

Alkyl radicals are named by replacing —ane of corresponding alkane by—yr.

 

Examples:

  
 

Formula

Name of Formula

 

RI slumber

of Name of

 

C-atoms

alkane

C,,H2n+2

Alkyl radical j CnH2n+1

 
 

CH4

Methyl i CH3

 

1

Methane

   

C2H6

Ethyl

C2H5

 

2

Ethane

 

3

Propane C3H8

Propyl

C3H7

 
  

Butane

C4H10

Butyl

C4H9

 
 
  

Pentane

C5H12

Panty

C51-111

 

5

 

6

Hexane

C6H14

Hexyl

C6H13

 

1–Heptyl

C7H15

7

Heptane

I C71-118

 

8

Octane

C8H18 Octyl

C5H17

 
 

9

Nonane

CgH20 Nonyl

CgHig

 

10

Decane

C10H22 Decyl C10H21

Activity 11.1:

Name the following alkyl groups

CH3CH2CH2-

ii. CH3CH2-

iv. CH3 (CH2)2CH2-

v. CH3 (CH2)4CH2-

Ans: iii. CH3

No.

Given Structural formula I Name of Aikyi rauical

 

CH3CH2CH2- or C3H7

Propyl

 

CH3CH2-.or C2H5

1 Ethyl

 

CH3

I Methyl

 

CH3(CH2)2CH2- or C4H9

f Butyl

 

CH3(CH2)4CH2- or C6H13

Hexyl

17. What is functional group? Explain with examples.

Ans. Functional group:

“An atom or group of atoms which replace the hydrogen atom in an alkane and give characteristic chemical properties to it is called functional group. “OR

“An atom or group of atoms which specify the chemical properties of an organic compound is called functional group. “OR

The active part of an organic compound is called functional group. Explanation:

A functional group is the active part of an organic compound. Most of the organic compounds consist of two parts .i.e.

i) The hydrocarbon part which is an alkyl group.

ii) The functional group part.

For example:

In methanol (CH3-OH), -CH3 is the alkyl group (R) while —OH is the functional group part.

Alkyl group(R) Functional group

Examples:

The most common functional groups are given in the table below:

Functional group

Name of the class

Example

Name of compound

-OH

Alcohols

CH3-OH

Methyl alcohol

-CHO

Aldehydes

CH3-CHO

Ethanol

-CO-

Ketones

CH3-CO-CH3

Propane

-COOH

Carboxylic acids

CH3-COOH

Ethanoic acid

-NH2

Amines

CH3-NH2

Methyl amine

-X

Alky halides

CH3-CI

, Methyl chloride

i

Ether

CH3-O-CH3

i Di methyl ether

.18. Explain the classification of functional groups? Ans. Classification of Functional Groups:

Functional groups can be classified into the following types:

i. Functional Groups Containing C, H and N:

Amines belong to functional groups containing carbon, hydrogen and nitrogen. The functional group of amines is -NH2 while the general formula for amines is R-NH2.

Example:

For example methyl-amine (CH3-NH2)

Ii. Functional Groups Containing C, H and 0:

Alcohols, carbonyl compounds (Aldehydes and ketones), carboxylic acids and their derivatives such as esters, acid halides and acid amides comes in this category. The detail is given below:

a. Alcoholic Functional Group:

The functional group of alcohols is -OH and general formula is R-OH where R stands for alkyl radical.

Examples:

i. Methyl alcohol (CH3-OH)

ii. Ethyl alcohol (C2H5-OH)

b. Ethers Functional Group:

The functional group of ethers is “-0-“and their general formula is-O-R.

Examples:

i. Di-methyl ether (CH3-O-CH3)

ii. Ethyl methyl ether (C2H5-O-CH3)

c. Carbonyl Functional Group:

A carbon atom doubly bonded to oxygen atom is called carbonyl 0 group(-c-). The compounds containing carbonyl group are called carbonyl compounds. These compounds are further classified to aldehydes and ketones.

Aldehydes:

These compounds have carbonyl carbon ( -o– ).The carbonyl group on one side is attached to H and on other side to alkyl group or hydrogen. Their general formula is

Example:

II IL

H—C—H CI-IS C—F1

Formaldehyde Acetaldehyde

Ketones:

These compounds have carbonyl carbon. The carbonyl group on which both side alkyl group is attached.

Their general formula R- C-R Examples:

CH3- C-CH3

Acetone

d. Carboxylic Acid Functional Grou2j

The functional group for carboxylic acids is –COOH. Their general formula is R-COOH.

Examples:

II II

0 0

CH3— C — OH H—C—OH

Acetic acid formic acid Hi. Functional Groups Containing C,H and Halogens:

Alkyl halides are the examples of this category. Their general formula is R-X.

Examples:

i. Methyl fluoride (CH3-F)

ii. Ethyl chloride (C2H5-Cpetc.

Activity 11.2:

Name the class of the compounds to which each of the following belongs:

i. CH3CH2CH3 ii. CH3CH2Br iii. CH3COOH

iv. C2H5CHO v. CH3CH2OH

Ans:

i. Name of the class = Alkane

Ii.Name of the class = Alkyl halide

Ii.Name of the class = Carboxylic acid

Ii.Name of the class = Aldehyde

V.Name of the class = Alcohol

word image 29

A. Choose the Correct Option.

1. The condensed structural formula of butane is.

a. CH3— CH2—CH2 –CH3 b. CH3 (CH) 2CH3 C. C4H10

2. The compounds C6H12 must have

a. All single bonds

c. At least one triple bond C— C— C— H H H H

b. At least one double bond

d. All double bonds

3. Which of the following is an inorganic compound?

a. CH4 b. CH3OH c. NaCN d. CH3CI

4. Alkyl halide is composed of carbon, hydrogen and

a. Oxygen b. Nitrogen c. Halogen d. Sulphur

5. Which of the following is an alcohol?

a. CH3-0— CH3 b. CH3— CH2— OH

c. CH3COOH d. CH3— COH

6. Unsaturated hydrocarbon is

a. C3H8 b. C2H6 c. C3H6 d. CH4

7. The functional group of ketone is

B. 9.

  1. b. — C¬ c. — c—OH d. —0-0–C-
  2. Natural gas is mainly composed of

a. CH4 b. C21-18 c. C2He d. C2H2

9. Catenation is the linkage of carbon with other

a. Oxygen atoms b. Carbon atoms

c. Nitrogen atom d. Halogens

10. Oxygen is attached on both sides to carbon atom in

a. Alcohol b. Ketone c. Aldehyde d. Ether

word image 30

Q. Define the functional group? Give some example of functional groups containing oxygen.

Ans: For answer see Question no.18

How can we obtain the organic compounds from natural sources?

For answer see Question no.9.

3. What are Cycloalkanes?

Ans: For answer see question no.15.

4. Write down examples of three unsaturated hydrocarbons with structural and condensed formulas?

Ans: Three unsaturated hydrocarbons with structural and condensed formulas:

(Structural Formula)

H H

I I

07– CH— —‘ H

H H

(Propene)

C= CH 1 H. H H H H

(Butane)

(Structural Formula)

H H H

I I I

C

=CH -5 – – 111 H H H

(Pentene) (Condensed Formula)

(CH2CHCH3)

(Propene)

(CH2CHCH20:13)

(Butane) (Condensed Formula)

(CH2CH (CH7)2CH3)

(Pentene)

Q.5. Define hydrocarbons, and briefly discuss their importance? Hydrocarbons:

“The compounds of carbon and hydrogen are called. Hydrocarbons.

Examples:

i. Methane (CH4)

ii. Acetylene (C2H2)

iii. Benzene (C61-16)

iv. Pentane (C5H12) etc.

Importance of hydrocarbons:

Hydrocarbons are very important in our daily life. They are used in almost all aspects of life. Some of them are given below:

. In medicines:

Many hydrocarbons are used in medicines.

Iii. In power generation:

Mixture of hydrocarbon like natural gas, petrol and diesel are used in power generation.

iv. As fuels:

Mixtures of hydrocarbons compounds like natural gas, petrol, kerosene and diesel etc. are used as fuels.

V. In industries:

Hydrocarbons are also used in industries.’

6. How alkyl radicals are formed? Discuss it with examples.

Ans. Formation of Alkyl Radicals:

Alkyl radicals are formed by removing one hydrogen atom from an alkane.

General formula:

The general formula of alkyl radical is CnH2n, 1, where n is the number of carbon atoms i.e. 1,2,3,4 etc.

General Symbol:

Alkyl radicals are denoted by a general symbol —R.

Naming an alkyl radical:

Alkyl radicals are named by replacing —ane of corresponding alkane by—yr

Examples:

Number of C-atoms

Name of alkane

Formula

CnH2n+2

Name of Alkyl radical

Formula

Run,. I-1 …2n+1

1

Methane

CH4

Methyl

CH3

2

Ethane

C2H6

Ethyl

C2H5

3

Propane

C3115

Propyl

C3H7

4

Butane

C4H10

Butyl

C4H9

5

Pentane

C51112

Panty

C5H1 i

6

Hexane

C6114

Hexyl

C61i13

7

Heptane

C71-116

Heptyl

C7H15

8

Octane

C8H18

Octyl

C51.117

9

Nonane

C9H2o Nonyl

C9H19

10

Decane

C10H22

Decyl

C101121

Q.7. List some uses of organic compounds?

Ans: For answer see Question no.10

Give the general molecular formulae of the following homologous series:

(a) Alkanes (b) alkenes (c) alkynes

Ans. (a) General Formula of Alkanes:

The general formula of alkanes is CnH2n+2.

Examples:

i. Methane (CH4)

ii. Ethane (C2H6) etc.

B. General Formula of Alkenes:

The general formula of a: knees are OnH2n-

Examples:

i. Ethene (C2H4)

ii.Propene (C3H6) etc.

C. General Formula of Alkanes:

The general formula of alkynes is C, H2n-2.

Examples:

i. Ethyne (C2H2) ii. Propene (C3H4) etc.

Q.9. Why organic compounds are volatile in nature?

Ans. Reason For Organic Compounds Being Volatile:

Volatile are those substances which easily evaporate and change into gaseous state at relatively low temperature. The volatility of a substance depends upon the strength of intermolecular attractive forces. Weaker the intermolecular attractive forces more volatile will be the substance and vice versa. Since organic compounds have generally weak inter molecular forces due to their non-polar nature that is why organic compounds are volatile in nature.

Q.10. Why is the chemical properties of a homologous series?

Ans. Reason for Homologous Series Having Same Chemical:

Properties:

The chemical! Properties of a homologous series depend on the functional group because it is the functional group which takes an active part in a chemicaireaction.

As all the mergers (homologues) of a homologous series have the same functional group that is why chemical properties of a homologous series are always the same.

word image 31

Ql. (a) List the different characteristics of organic compounds.

Ans: For answer see question no.8

(b) Which of these is not an unsaturated molecule?

C41-16 (ii) C6H6 (iii) C8H18 (IV) C31-16

Ans: Way to find saturated molecule is a tul rated:

Saturated hydrocarbon molecule can easily be found by comparing the molecule with the general formula.

General Formula:

The general formula of saturated hydrocarbon molecule is C, 1-12:1, 2 Molecule which is not unsaturated:

Molecule no. iii C8H-i8 is not an unsaturated molecule because it is a saturated molecule and it fully satisfies the general formula of saturated hydrocarbons i.e. alkanes In C8I-118; n=8 therefore putting the value in general formula we get;

C8H2 (8) +2 = C8H18 –

Other molecules given, do not fit with the general formula of saturated hydrocarbons therefore, they are unsaturated molecules. (c).Define destructive distillation of coal.

Name the different types of products obtained by the destructive distillation of coal.

• Ans: For answer see question no.9 2.

  1. What is catenation?

Ans: For answer see question no.7

(b)How does catenation contribute to the diversity of organic compounds?

Ans. Contribution of catenation in diversity of organic compounds:

Due to catenation carbon atoms can arrange themselves in different ways due to which different compounds are formed. Thus we have large varieties of organic compounds. The same no. of carbon can arrange ihernselves to form different compounds.

Examples:

CH, — C H—- CH,

– I

CI-13

(Iso-butane)

CH3— CH2 — CH2 – – – CH3

(N-butane)

(A) What information about a compound is provided by a structural formula?

Ans. Structural Formula:

This formula represents the arrangement of different atoms of various elements around the carbon atoms present in a molecule of a compound.”

Information provide by structural formula:

i. Structural formula shows the nature and type of atoms present in a molecule of a compound.

ii. It shows the bonding arrangement of atoms.

iii. It shows us the total no. of bonds formed by an atom.

iv. It also shows the total no. of atoms in a molecule.

v. It gives idea about the shape of molecule.

Examples:

Structural formulas of some compounds are given below:

HI H H H H

I I I

H—C —HC—H C—H

I I I I

H H H H H H

(Methane) (Ethane) (Propane)

(b). How are structural formulae used in organic chemistry?

Ans. Use of structural formula in organic chemistry:

Structural formula is widely used in organic chemistry in order to know the real arrangement of atoms. Due to this formula properties of the compounds can also be predicted.

There are a large number of organic compounds having same chemical formula but different structural formulas. These compounds can only be differentiated from one another by the use of structural formula.

Examples:

CH3—C H—CH3

CH3

(Iso-butane)

CH,—CH_—CH2—CH, n-butane)

Q.4. (a) what do the terms saturated and unsaturated mean when applied to hydrocarbons?

Ans. Meaning of the term saturated and unsaturated in h drocarbons:

• The term saturated in hydrocarbons means those hydrocarbons in which the carbon atoms forms four single bonds, carbon atom is directly attached with four other atoms while unsaturated hydrocarbons Means that in these hydrocarbons carbon atom forms at least one double or triple bond.

Saturated hydrocarbons are also called alkanes while unsaturated hydrocarbons have two types’ alkenes and alkynes.

i. Saturated hydrocarbons examples:

a. CH,—CH,–CH,—CH, (n-butane)

b. CH3—C71,—CH, (n-propane)

Unsaturated hyclrocarbons

Examples:

a. CH;—CH (, g-butane or 2- butane)

b. CH —C=C—CH303—butane or 2- butane)

(b). what other meanings do these terms have in chemistry? Ms. other meanings of saturated and unsaturated:

In addition to hydrocarbons saturated and unsaturated terms are applied to types of solutions also they are discussed below:

Saturated solution:

“The type of solution which cannot dissolve more solute at a given temperature is called saturated solution.

Unsaturated solution:

“The type of solution which can dissolve more solute at a given temperature is called saturated solution.”

(c). Classify alkenes, alkanes, alkynes, and aromatic hydrocarbons as either saturated or unsaturated.

Ans. Classification of the given classes as saturated or unsaturated:

• Saturated hydrocarbons are those in which carbon atoms have single bonds only while in unsaturated hydrocarbons carbon atoms may have double or triple bonds.

Alkanes as saturated hydrocarbons:

Alkanes are saturated hydrocarbons because in thee carbon atoms have single bonds only.

Examples:

a. CH3 — CH, —CH, Ch’3 (n-butane)

b. CH3— CH2 -CH; (n-propane) etc.

Alkenes, alkynes and aromatic hydrocarbons as unsaturated hydrocarbons:

Alkenes, alkynes and aromatic hydrocarbons are u saturated hydrocarbons because alkenes contain carbon-carbon double bonds, alkynes contain carbon-carbon triple bonds while aromatic compounds contain alternate double and single bonds between the carbon atoms.

Examples:

A. Alkene CH,–CH =CH —CH (13—butane or 2- butane)

B. Alkyne CH,—C =C—CH, (B—butane or 2- butane)

c. Aromatic compound

Benzene

Q5. (a)Can you explain the term ilumultiyou* series?

Ans: For answer see Question no.14

(b) How the straight —chain hydrocarbons are named?

Ans: For answer see Question no.13

(c) Name the straight —Chain alkane with the molecular formula C8 H18

Ans: Structural formula:

CH3—CH: — CH: — CH,—C11,–CH2—CH,–CH,

Name of the compound:

The name of the compound, having straight chain, with molecular formula C8 H18 is n-octane where n stands for normal.

Additional Questions 1

Q. Briefly discuss how organic and inorganic compounds differ?

Ans: Difference between organic and inorganic compounds:

The difference between organic and inorganic compounds is given in the table below:

Organic compounds Inorganic compounds

“Hydrocarbons and their derivatives are called organic compounds.”

“The compounds of all elements except hydrocarbons and their derivatives are called inorganic compounds.”

They are mostly found in the bodies of living organisms.

They are mostly found in earth crust.

Most of the organic compounds are combustible.

Most of the inorganic compounds are non-combustible.

Most of the organic compounds are non-polar.

Most of the inorganic compounds are polar.

All the organic compounds have covalent bonds in them.

Inorganic compounds have covalent as well as ionic bond in them.

Most of them are thermally unstable.

Most of them are thermally stable.

Most of them dissolve in non-polar solvents like benzene, acetone etc.

Most of them dissolve in polar solvents like water.

Their reactions are slower than inorganic compounds.

Their reactions are faster as compared to organic compounds.

Most of the organic compounds are volatile.

Most of the inorganic compounds are non-volatile.

Examples:

i. Alkanes like methane, ethane etc.

ii. Alkenes like Ethene, propene etc.

iii. Alkynes like Ethyne, propyneetc

iv. Alcohols like methyl alcohol, ethyl alcohols etc.

Examples:

i. Acids like hydrochloric acid, nitric acid etc.

ii. Salts like sodium chloride, potassium chloride etc.

iii. Bases like sodium hydroxide, aluminum hydroxide etc.

iv. Carbon monoxide

Carbon dioxide etc.

Additional Multiple Choice Questions 1

1. Which of the following is organic compound?

(a) CO. (b) CO2 (c) NaHCO3. (d)C2H2.

2. Which one of the following is the general formula of alkanes’

(a) C, H2n.2. (b) CaH2n-.1. (c) (d) CoH2p-2

3. The homologous have the same:

(a) State. (b) Colour. (c) Density (d) Chemical properties.

4. Carbon atom usually:

(a)Forms for covalent bonds. (b) Gains four electrons.

(c) Loses for electrons. (d) Ionizes.

5. Organic radical with general formula CnE-12, .1 is.

(a)Phenyl (b) benzyl. (c) Alkyl. (d) Alkyl.

6. The next homologue of C8H18 is:

(a) C8H16 (b) CsH2o (c) COHE (d) C71114.

7. Methane is the first member of:

(a) Alkane series (b) alkenes series

(c) Alcohol series (d) carboxylic acids series

8. The compound C3H8 must have:

(a) All single bonds (b) at least one double bond

(c) At least one triple bond (d) an ionic bond.

9. Organic compounds are originated from:

(a) Air (b) rock (c) sun (d) living organism.

10. The name of C6H14 is:

(a) Propane (b) heptane’s (c) hexane (d) Decane.

11. Which one of the following organic compounds has different chemical properties?

(a) CH3OH (b) C2H5COOH (c) C2H5OH (d) C51-1110H

12. Which of the following is inorganic?

(a) CH4 (b) CH3OH (c) NaCN (d) CH3CI.

13. In 1828 A.D vital force theory was rejected by:

(a) Friedrich Wohler (b) Mosley

(c) John Dalton (d) J.J. Thomson.

14. Organic compound was among the first that was synthesized in

Laboratory.

(a) Urea (b) chloroform (c) penicillin (d) C2H5OH.

15. Wohler synthesized urea from:

(a) NH4CNO (b) KCN (d) NaCN.

16. Natural gas contains % methane.

(a) 85% (b) 90% (c) 70% (d) 60%

17. In n-alkane carbon atom are held to other carbon atoms.

(a) Three (b) two (c) one (d) four.

18. gives characteristics okay o:-.-2:,, retires to a r.n.:;!ece

(a) Functional group 2‘k’or-lologue

(c) Alkyl groups no any group.

19. Organic compounds are generally in nature.

(a) Ionic (b) covalent (c) coordinate (d) free radical.

20. The homologous have the same .

(a) State (b) colour (c) density (d) chemical properties.

21. Is a major source of organic compounds?

(a) Coal (b) rock (c) minerals (d) sand.

22. Organic compounds are originated from:

(a) Air (b) rock (c) sun (d) living organisms.

23. Which one is organic compound?

(a) CO (b) CO2 (c) Na2CO3 (d) C2112.

24. The general formula of alkyl radical is

(a) CnH2n (b) CnH2n+1 (C) CnH2n+2 (d) CnH2n -2.

25. The functional group of alkyl halide is .

(A) R-OH (b) HX (c) -COH (d)R-X

26. The functional group of carboxylic acid is:

(A) -OH (b) —CO— (c) —COOH (d) -COH.

27. The general formula of alkynes is.

(A) nH2n+2. (b) CnH2n, i (c) CnH2r (d) CnH2n-2

28. Which one of the following organic compounds is an alcohol?

(a)CH3COCH3 (b) C2H5CHO

(C) C3H7OH (d) CH3COOH

2 thoughts on “CLASS 10th CHEMISTRY NOTES CHAPTER 11 ORGANIC CHEMISTRY”

  1. Pingback: CLASS 10th CHEMISTRY NOTES CHAPTER 12 HYDROCARBONS - Daraz 24

  2. Pingback: Federal Board of Intermediate and Secondary Education 2021 Result - Daraz 24

Leave a Reply

Scroll to Top
%d bloggers like this: