Chapter 9 -Carbon Compounds.

02 Nov 2020 7:49 pm

Question 1:

Match the pairs.

Group ‘A’Group ‘B’
a. C2H61. Unsaturated hydrocarbon
b. C2H22. Molecular formula of an alcohol
c. CH4O3. Saturated hydrocarbon
d. C3H64. Triple bond
ANSWER:
Group ‘A’Group ‘B’
a. C2H61. Saturated hydrocarbon
b. C2H22. Triple bond
c. CH4O3. Molecular formula of an alcohol
d. C3H64. Unsaturated hydrocarbon 
Question 2:
Draw an electron dot structure of the following molecules. (Without showing the circles)

a. Methane

b. Ethene

c. Methanol

d. Water

ANSWER:

Question 3:
Draw all possible structural formulae of compounds from their molecular formula given below.
a. C3H8  
b. C4H10  
c. C3H
ANSWER:
Question 4:
Explain the following terms with example.

a. Structural isomerism

b. Covalent bond

c. Hetero atom in a carbon compound

d. Functional group

e. Alkane

f. Unsaturated hydrocarbon

g. Homopolymer

h. Monomer

i. Reduction

j. Oxidant

a. Structural isomerism: -Structural isomerism or constitutional isomerism is a form of isomerism in which molecules have same molecular formula but different arrangements of the atoms in space.

Different arrangement may be in bonding patterns and atomic organization.

For example: CH3OCH3 and CH3CH2OH are structural isomers.

b. Covalent bond: -Covalent bond is a chemical bond that involves the sharing of electron pairs between atoms.

These electron pairs are known as shared pairs or bonding pairs.

It is also known as molecular bond.

For example: Molecules that have covalent linkages are hydrogen, nitrogen, chlorine, water, and ammonia (H2, N2, Cl2, H2O, NH3).

A single line indicates a single bond between two atoms (i.e.involving one electron pair), double lines (=) indicate a double bond between two atoms (i.e. involving two electron pairs), and triple lines (≡) represent a triple bond (C≡O).


c. Hetero atom in a carbon compound: It is a compound formed by replacement of carbon and hydrogen by heteroatom in a compound.

A heteroatom is any atom other than carbon or hydrogen.

Typical heteroatoms are nitrogen, oxygen, sulfur, phosphorus, chlorine, bromine, and iodine.

Similarly, Nitrogen is the hetero atom in Ethyl amine ( CH3-CH2NH2


d. Functional group: The functional group is defined as an atom or group of atoms joined in a specific manner, which gives the chemical properties of the organic compound and they are the centers for chemical reactivity.

Compounds having a similar functional group undergoes similar reactions.

For example:


1. Alkane: The functional group presence in the alkane is -C-C-. The IUPAC group suffix of an alkane is –ane.

Example: Methane CH4


2. Alkene: The functional group presence in the alkene is -C=C- (double bond). The IUPAC group suffix of an alkene is –ene.

Example: butane


3. Alkynes: The functional group presence in the alkyne is -C ≡ C- (triple bond). The IUPAC group suffix of an alkyne is –yne.

Example: Propyne

4. Arenes: They contain a benzene ring as the functional group.

Example: Benzene


5. Halides: The functional group presence in halides is X(halogen).

Example: Chloromethane


6. Alcohols: The functional group, which is present in alcohol, is -OH. The IUPAC group suffix of alcohol is –ol.

Example: Ethanol

7. Aldehydes: The functional group, which is present in an aldehyde, is -CHO. The IUPAC group suffix of an aldehyde is –al.

Example: Formaldehyde

8. Ketones: The functional group, which is present in a ketone is >C=O. The IUPAC group suffix of a ketone is –one.
Example: Acetone

9. Carboxylic acid: The functional group present in a carboxylic acid is -COOH. The IUPAC group suffix of a carboxylic acid is –oic acid.

Example: Acetic acid

10. Amine: The functional groups present in an amine are -NH2>NH>N- The IUPAC group prefix of an amine is amino– or the suffix is –amine.
Example: Methylamine

11. Ester: The functional group present in an ester is -COOR The IUPAC group suffix of an ester is –ate.
Example: Ethyl acetate

e. Alkane: Alkane is a saturated hydrocarbon.

It is formed when there is sharing of one electron pair between carbon atoms in a compound.

The general formula for alkane is CNH2N+2, where N is equal to no of carbon atoms in a compound.

For example:

C2H6Ethane
C3H8propane
C4H10butane
C5H12pentane
C6H14hexane
C7H16heptane
C8H18octane
C9H20nonane
C10H22decane
C11H24undecane

f. Unsaturated hydrocarbon: An unsaturated hydrocarbon is a hydrocarbon containing at least one double or triple bond.

For example: Alkenes – These unsaturated hydrocarbons are molecules that contain at least one carbon-to-carbon double bond.

With the chemical formula consisting of CnH2n.

The simplest alkene is ethylene.

Alkynes – These unsaturated hydrocarbons are molecules that contain at least one carbon-to-carbon triple bond. 

Acetylenes are common examples of alkynes.

g. Homopolymer: A homopolymer is a polymer formed from the same type of monomer units.

For examples:

Polyvinylchloride (PVC),

Polyethylene,

Polystyrene are homopolymer.

h. Monomer: A monomer is a molecule that forms the basic unit for polymers.
They may be considered as building blocks from which proteins are made.
Monomers may bind to other monomer unit to form a repeating chain molecule.
Monomers may be either natural or synthetic in origin.

For example:

Ethylene,

vinyl chloride,

styrene etc.

i. Reduction: The addition of hydrogen to a substance is called reduction.
The removal of oxygen from a substance is called reduction.
For example:2Ag2O → 4 Ag + O2
In a reaction, silver oxide is changing to silver.
That is, oxygen is being removed from silver oxide.
Removal of oxygen from a substance is called reduction, so silver oxide undergoes reduction.
NiO + H2 → Ni + H2O
In a reaction, Nickel oxide is changing to nickel.
That is, oxygen is being removed from nickel oxide.
Removal of oxygen from a substance is called reduction, so nickel oxide undergoes reduction.
In a reaction, hydrogen is changing to H2O.
That is, oxygen is being added to hydrogen.
Addition of oxygen to a substance is called oxidation, so hydrogen undergoes oxidation.

j. Oxidant:The substance which gives oxygen for oxidation is called an oxidizing agent or oxidant.
The substance which removes hydrogen is called an oxidizing agent or oxidant.

For example:
CuO + H2 → Cu +  H2O Oxidising agent=CuO Reducing agent= H2 Substance oxidised=H2Substance reduced=CuO
ANSWER:
Question 5:
Write the IUPAC names of the following structural formulae.
a. CH3-CH2-CH2-CH3b. CH3-CH2-CH2-CH3
c. CH3-CHOH-CH3d. CH3-CHOH-CH3
e. CH3-CH2-COOHf. CH3-CH2-COOH
ANSWER:

a. CH3-CH2-CH2-CH3 = Butane
b. CH3-CH(OH)-CH3 = Propan-2-ol
c. CH3-CH2-COOH = Propanoic acid
d. CH3-CH2-NH2 = Ethan-1-amine
e. CH3-CHO = Ethanal
f. CH3-CO-CH2-CH3 = Butanone

Question 6:
Identify the type of the following reaction of carbon compounds.

a. CH3 -CH2 -CH2-OH → CH3 -CH2 -COOH

b. CH3 -CH2 -CH3 → 3CO2 + 4H2O

c. CH3 -CH = CH -CH3 + Br2 → CH3 -CHBr – CHBr -CH3

d. CH3 -CH3 + Cl2 → CH3 -CH2 -Cl + HCl

e. CH3 -CH2 -CH2 -CH2 -OH → CH3 -CH2 -CH=CH2 + H2O

f. CH3 -CH2 -COOH + NaOH → CH3 -CH2 -COO – Na+ + H2O

g. CH3 -COOH + CH3 -OH → CH3 -COO- CH3 + H2O

ANSWER:

a. CH3 -CH2 -CH2-OH → CH3 -CH2 -COOH = Oxidation reaction(acidic KMnO4)

b. CH3 -CH2 -CH3 → 3 CO2 + 4H2O = Combustion reaction

d. CH3 -CH3 + Cl2 → CH3 -CH2 -Cl + HCl = Substitution reaction

e. CH3 -CH2 -CH2 -CH2 -OH → CH3 -CH2 -CH=CH2 + H2O = Dehydration reaction

f. CH3 -CH2 -COOH + NaOH → CH3 -CH2 -COO – Na+ + H2O = Neutralization reaction(reaction with base)

g. CH3 -COOH + CH3 -OH → CH3 -COO- CH3 + H2O = Esterification reaction

Question 7:

Write structural formulae for the following IUPAC names.

a. pent-2-oneb. 2-chlorobutane
c. propan- 2 old. methanal
e. butanoic acidf. 1-bromopropane
g. ethanamineh. butanone

ANSWER:


Question 8:
Write answers as directed.
a. What causes the existence of very large number of carbon compound ?
b. Saturated hydrocarbons are classified into three types. Write these names giving one example each.
c. Give any four functional groups containing oxygen as the heteroatom in it. Write name and structural formula of one example each.
d. Give names of three functional groups containing three different hetero atoms. Write name and structural formula of one example each.
e. Give names of three natural polymers. Write the place of their occurrence and names of monomers from which they are formed.
f. What is meant by vinegar and gasohol? What are their uses ?
g. What is a catalyst ? Write any one reaction which is brought about by the use of catalyst ?
ANSWER:

a. Organic compounds mean carbon compounds.

Carbon is unique element in the periodic table.

It has 4 valence electrons.

That means each individual carbon atom can bind to 4 other atoms of almost any variety and each of those 4 can bind to 4 other atoms.

This leads to the formation of organic compounds having incredible variety and complexity – short chains, long chains, ring structures, branched structures and so on.

This self linking property of carbon atom is called catenation, which leads to the existence of a very large number of carbon compounds.


b. Saturated hydrocarbons are classified into three types:
Saturated hydrocarbonExampleStructure
1) Straight chain hydrocarbonsPropane C3H8
2)Branched chain hydrocarbonisobutane C4H10
3)Cyclic hydrocarbonCyclohexane C6H12
c. Four functional groups containing oxygen as the heteroatom in it are as follows:


1. Alcohols: The functional group, which is present in alcohol, is -OH. The IUPAC group suffix of alcohol is –ol. Example: Ethanol

2. Aldehydes: The functional group, which is present in an aldehyde, is -CHO. The IUPAC group suffix of an aldehyde is –al. Example: Formaldehyde

3. Ketones: The functional group, which is present in a ketone is >C=O. The IUPAC group suffix of a ketone is –one. Example: Acetone

4. Carboxylic acid: The functional group present in a carboxylic acid is -COOH. The IUPAC group suffix of a carboxylic acid is –oic acid. Example: Acetic acid

d. Three functional groups containing three different hetero atoms are as follows: Carboxylic acid:

The functional group present in a carboxylic acid is -COOH.

The IUPAC group suffix of a carboxylic acid is –oic acid.

Here, heteroatom is oxygen.


Example: Acetic acid

Amine: The functional groups present in an amine are -NH2>NH>N- The IUPAC group prefix of an amine is amino– or the suffix is –amine. Here, heteroatom is nitrogen.
Example: Methylamine

Halo: The functional group presence in halides is X (halogen= F,Cl,Br,I). Here, heteroatom is chloride. Example: Chloromethane.

e. Give names of three natural polymers. Write the place of their occurrence and names of monomers from which they are formed.
ANSWER:
Natural polymers     Monomer unitOccurrence
1.PolysaccarideGlucose  Starch
2.Cellulose   Glucose     Wood (cell wall of plant cells)
3.Proteins      Alpha aminoacids   Muscles, hair, Skin, Egg
4.D.N.A       Nucleotide(base-deoxyribose-phosphate) Chromosomes of animals
5.R.N.A      Nucleotide(base-ribose-phosphate )   Chromosomes of plants
6.Rubber    Isoprene(CH2=C(CH3)-CH=CH2 )   Latex of rubber tree

f. Vinegar is the type of liquid which consist of acetic acid ( Ethanoic acid ). It is basically produced by the process of fermentation of ethanol through ethanoic acid in the presence of bacteria


Reaction involved in the formation of Vinegar:

CH₃CH₂OH + O₂→ CH₃COOH + H₂O Fermentation is the process of converting sugar into alcohol.

But if the cork of the bottle open for sometimes then there is the second type of fermentation happened. 

In this process, alcohol is changes into acetic acid, so the main compound which formed is vinegar.

Uses of Vinegar are:

It is used in the preparation of the food .

It is used in pickling.
It is used as folk medicine material.
It is used as a household cleaning agent.
Gasohol is a mixture of 90% gasoline and 10% of anhydrous Alcohol (Ethyl Alcohol).
It is commonly known as the alternative fuel or a motor fuel.

Benefits of gasohol are :-

It is cheaper.
It is eco-friendly.
It has higher performance.
It is used as a cleaner to the environment.
It doesn’t freeze in typical conditions.

Uses of gasohol are:

It is used in a fuel or petroleum Industry.
It is used in an automobile industry.
It is used as common gasoline or hydrous around the world.
It is used as a flexible fuel vehicle, because it does not freeze in typical conditions.

g. Catalyst is a substance that increases the rate of a chemical reaction without itself undergoing any permanent chemical change.
For example:
E.g.Name of processEquations (in words or formulae)Catalyst
1Fermentation of glucose to form ethanolGlucose → Ethanol + Carbon dioxideSpecific enzymes (in yeast)
2Hydration of ethene to form ethanolEthene + Water (Steam) Heat → EthanolPhosphoric Acid
3Hydrogenation of unsaturated fats(to harden oils in the manufacture of margarine)Hydrogen + Unsaturated Fats → Saturated Fats
Nickel (Ni)
4Haber’s processNitrogen +Hydrogen → AmmoniaIron

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