Chemical Reactions Of Organic Compounds
Class 10th Chemistry Part Ii Kerala Board Solution
- Given below are two chemical equations. a) CH2 = CH2 + H2→ A b) Identify the compounds “A”…
- Name the important chemical reactions of hydrocarbons. Give one example for each.…
- Write the chemical formula of propane. Write the names and structural formulae of two…
- Complete the equation for the following chemical reaction. Name this reaction. CH3 - CH2 -…
- Which of the given molecules can form polymers? Butane, Propane, Propene, Methane, Butene…
Let Us Assess
Question 1.Given below are two chemical equations.
a) CH2 = CH2 + H2→ A
b) 
Identify the compounds “A” and “B”. Name these reactions.
Answer:
a) “A” is CH3—CH3 (ethane)
When an unsaturated hydrocarbon reacts with hydrogen, gives a saturated hydrocarbon. This reaction is called addition reaction.
CH2 = CH2 + H2→ CH3—CH3 (A)
(unsaturated) (saturated)
Note: Unsaturated hydrocarbons are those which contain carbon to carbon double bonds C=C or carbon to carbon triple bonds -CΞC- in their molecules.
Saturated hydrocarbons are those organic compounds which contain carbon–carbon single bond.
b) CH3—CH3 + Cl2→ CH3—CH2—Cl + HCl
EthaneChloroethane
(A) (B)
Question 2.
Name the important chemical reactions of hydrocarbons. Give one example for each.
Answer:
Important chemical reactions of hydrocarbons are:
i. Substitution reaction:
Reaction in which an atom or a group in a compound is replaced by another atom or group are called substitution reactions.
Example:
Methane Chloromethane
In the above example, one hydrogen atom of methane is replaced by one chlorine atom.
ii. Addition reaction
When an unsaturated hydrocarbon reacts with hydrogen, gives a saturated hydrocarbon. This reaction is called addition reaction.
Example:
CH2 = CH2 + H2→ CH3—CH3
(unsaturated) (saturated)
iii. Polymerization
Polymerization is a process in which a large number of simple molecules combine under suitable conditions to form complex molecules. The molecules formed are called polymers.
Example:
In the above reaction, a large number of ethene molecules combine under higher pressure in the presence of catalyst to form polythene.
Question 3.
Write the chemical formula of propane. Write the names and structural formulae of two compounds that may be formed during its substitution reaction with chlorine.
Answer:
The chemical formula of propane: CH3—CH2—CH3
Substitution reaction of propane with chlorine:
i. CH3—CH2—CH3 + Cl2 → CH3—CH2—CH2—Cl
propane 1-chloropropane
ii. 
Propane 2-chloropropane
Question 4.
Complete the equation for the following chemical reaction. Name this reaction.
CH3 – CH2 – CH2 – CH3 + ... Ο2 → __________ + __________
Answer:
Equation is:
CH3—CH2—CH2—CH3 + O2→ CO2 + H2O
Balanced equation:
2C4H10 + 13O2→ 8CO2 + 10H2O
Butane
The above reaction is a combustion reaction.
When hydrocarbons burn, they combine with the oxygen in the air to form CO2 along with heat and light. The reaction takes place is called combustion.
Question 5.
Which of the given molecules can form polymers? Butane, Propane, Propene, Methane, Butene
Answer:
Propene and butene
Unsaturated hydrocarbons undergo polymerization reaction to form a large number of saturated hydrocarbons.
Propene undergoes polymerization:
Butene undergoes polymerization:
Extended Activities
Question 1.You are familiar with different chemical reactions of hydrocarbons. Identify the situations in daily life in which these are used.
Answer:
i. Manufacture of polymers like polythene.
ii. Production of rubbers.
iii. In lubricants like grease and graphite.
iv. Photosynthesis by plants
v. Burning of matchstick
vi. Burning of coal.
Question 2.
List the different uses of ethanol. Prepare an essay on its adverse effects on human body and the related social issues when it is used as a beverage.
Answer:
Uses of ethanol:
i. Ethanol is extensively used for industrial purposes.
ii. It is used as an organic solvent.
iii. It is used in the manufacture of various organic compounds.
iv. It is used in the manufacture of paints.
v. It can be used as a fuel.
vi. It is used as a preservative.
Adverse effects of ethanol:
i. Ethanol consumption direct effects the nervous system (especially brain) and liver.
ii. The ability of memorization and learning becomes slow.
iii. Due to excess consumption of ethanol, lifespan of a person also decreases.
Question 3.
You know how to make soap, don't you? Try to prepare soaps of different colours and fragrance. Prepare a short note on the chemistry of soaps.
Answer:
Chemistry of soaps:
i. Soaps are sodium and potassium salts of fatty acids.
ii. They are produced by the process of saponification.
iii. Saponification is a process in which natural oils or fats undergo hydrolysis to produce soaps.
iv. It comes in the form of solid bar or liquid gels.
v. It is an excellent skin cleanser.
vi. It is also used in laundry for cleaning a large number of textiles.
