Organic Chemistry Intext-1 Concise Class-10 ICSE Chemistry Selina Solutions Chapter-12. We Provide Step by Step Answer of Intext-1 Questions of Exercise-12 for ICSE Class-10. The given Solutions is according to the Latest editions. Visit official Website CISCE for detail information about ICSE Board Class-10.

Organic Chemistry Intext-1 Concise Class-10 ICSE Chemistry Selina Solutions Chapter-12

Board	ICSE
Book / Publication	Concise / Selina
Subject	Chemistry
Class	10th
Writer	Dr SP Singh
Chapter-12	Organic Chemistry
Topics	Intext-1
Edition	2025-2026

Intext-1 on Organic Chemistry

Page-193

Que-1: 

(a) What are organic compounds?
(b) What is the Vital force theory? Why was it discarded?

Ans:
(a) Organic chemistry may be defined as the chemistry of hydrocarbons and its derivatives.
(b) Vital Force Theory is a theory made by the Scientist Berzelius in 1809 which assumed that organic compounds are only formed in living cells and it is impossible to prepare them in laboratories.
It was discarded because Friedrich Wohler showed that it was possible to obtain an organic compound(urea) in the laboratory.

Que-2: 

(a) Name a few sources of organic compounds
(b) Give the various applications of organic chemistry

Ans:
(a) Few sources of organic compounds are:
Plants
Animals
Coal
Petroleum
Wood
(b) The various applications of organic chemistry is:
It is used in the production of soaps, shampoos, powders and perfumes.
Various fuels like natural gas, petroleum are also organic compounds.
The fabrics that we use to make various dresses are also made from organic compounds.

Que-3: Organic chemistry plays a key role in all walks of life. Discuss

Ans: Organic compounds are present everywhere. They are present in:
It is present in the production of soaps, shampoos, powders and perfumes.
It is present in the food we eat like carbohydrates, proteins, fats, vitamins etc.
Fuel like natural gas, petroleum are also organic compounds.
Medicines, explosives, dyes, insecticides are all organic compounds.
Thus we can say that organic compounds play a key role in all walks of life.

Que-4: Carbon shows some unique properties, name them.

Ans: The unique properties shown by carbon are:
Tetravalency of carbon
Catenation
Isomerism

Que-5: Explain the following:

(a) Tetra valency
(b) Catenation

Ans:
(a) Tetra valency: Carbon can neither lose nor gain electrons to attain octet. Thus it shares four electrons with other atoms. This characteristics of carbon by virtue of which it forms four covalent bonds, is called Tetra valency of carbon.
(b) Catenation: The property of self -linking of atoms of an element through covalent bonds in order to form straight chains, branched chains and cyclic chains of different sizes is known as catenation.
Carbon- carbon bond is strong so carbon can combine with other carbon atoms to form chains or rings and can involve single, double and triple bonds.

Que-6: Write any four properties of organic compounds that distinguish them from inorganic compounds.

Ans: Four properties of organic compound that distinguish them from inorganic compounds are:
(i) Presence of carbon.
(ii) Solubility in the organic solvents.
(iii) Forming of covalent bonds.
(iv) Having low melting and boiling points.

Que-7: Why are organic compounds studied as a separate branch of chemistry?

Ans: Due to the unique nature of carbon atom, it gives rise to formation of large number of compounds. Thus this demands a separate branch of chemistry.

Que-8: What are Hydrocarbons? Compare saturated and unsaturated hydrocarbons?

Ans: Hydrocarbons are compounds that are made up of only carbon and hydrogen.
Comparison of saturated and Unsaturated hydrocarbons:

Saturated Hydrocarbon	Unsaturated Hydrocarbon
1. Carbon atoms are joined only by single bonds.	Carbon atoms are joined by double or by triple bonds.
2. They are less reactive due to the non-availability of electrons in the single covalent bond.	They are more reactive due to presence of electrons in the double or the triple bond.
3. They undergo substitution reaction.	They undergo addition reaction.

Que-9: Give reason for the existence of large numbers of organic compounds

Ans: Due to presence of unique properties of carbon like Tetravalency, catenation and Isomerism large number of organic compounds are formed.

Que-10: Give at least one example in each case to show structure of isomers of

(a) Single bond compound
(b) Double bond compound
(c) Triple bond Compound

Ans:
(a) Single Bond compound: For example: In pentane

(b) Double bond compound: For example:- In pentene

(c) Triple bond compound: In case of Hexyne:

Que-11: Name a compound of each type and draw the figure.

(a) Cyclic compound with single bond
(b) Cyclic compound with triple bond

Ans:
(a) Cyclic compound with single bond: cyclopentane
Structure:

(b) Cyclic compound with triple bond: cyclopentyne
Structure:

Que-12: Give the name of one member of each of the following:

(a) Saturated hydrocarbons
(b) Unsaturated hydrocarbons

Ans: The member of each of the following is:
(a) Saturated Hydrocarbon: Hexane (C6H14)
(b) Unsaturated Hydrocarbon: Hexene (C6H12)

Que-13: Define substitution and addition reaction .Give an example for each.

Ans:
Substitution reaction: A reaction in which one atom of a molecule is replaced by another atom (or group of atoms) is called a substitution reaction.
Addition reaction: A reaction involving addition of atom(s) or molecules(s) to the double or the triple bond of an unsaturated compound so as to yield a saturated product is known as addition reaction.

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