Page 278 - Chemistry ICSE Class X

264 ICSE Chemistry – 10

The compounds having a ring Some examples of multiple bond formation are given below:
containing carbon atoms are called
cyclic compounds͘

dŚĞ ŝŽŶŝƐĂƟŽŶ ĞŶĞƌŐLJ ŽĨ ĐĂƌďŽŶ ŝƐ
ǀĞƌLJ ŚŝŐŚ͘ ĂƌďŽŶ ŝƐ ŵŽĚĞƌĂƚĞůLJ
ĞůĞĐƚƌŽŶĞŐĂƟǀĞ͘ dŚƵƐ͕ ĐĂƌďŽŶ ŚĂƐ ŶŽ ƒ Formation of strong covalent bonds. Carbon atoms form very strong
ƚĞŶĚĞŶĐLJ ƚŽ ůŽƐĞ Žƌ ŐĂŝŶ ĞůĞĐƚƌŽŶƐ͘
Ɛ Ă ƌĞƐƵůƚ͕ ŝƚ ĨŽƌŵƐ ďŽŶĚƐ ŽŶůLJ ďLJ covalent bonds due to its small size.
ŵƵƚƵĂů ƐŚĂƌŝŶŐ ŽĨ ĞůĞĐƚƌŽŶƐ͕ ŝ͘Ğ͕͘ ƒ Isomerism. Most carbon compounds show isomerism. That is why
ĐŽǀĂůĞŶƚ ďŽŶĚƐ͘ carbon forms a large number of compounds.
ͻ
The compounds having the same For example, the molecular formula C H O describes two compounds
2
6
ŵŽůĞĐƵůĂƌ ĨŽƌŵƵůĂ ďƵƚ ĚŝīĞƌĞŶƚ having the structural formulae.
ƐƚƌƵĐƚƵƌĞ ĨŽƌŵƵůĂĞ ĂƌĞ ĐĂůůĞĚ isomers CH – CH OH CH – O – CH
ĂŶĚ ƚŚŝƐ ƉƌŽƉĞƌƚLJ ŝƐ ĐĂůůĞĚ ŝƐŽŵĞƌŝƐŵ͘ 3 2 3 3
ethyl alcohol (ethanol) dimethyl ether (methoxymethane)
The isomers show different properties.

Types of Organic Compounds

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FGTKXCVKXGU $CUGF QP VJKU FGſPKVKQP VJG QTICPKE EQORQWPFU CTG ENCUUKſGF
into various families. These are:

Family Characteristic feature Example
1. Hydrocarbon
Ŗ alkane CH , C H 6
2
4
Ŗ alkene C H , C H 6
4
2
3
Ŗ alkyne C H , C H 4
2
2
3
2. Alcohol CH OH, C H OH
3
5
2
3. Aldehyde CH CHO
3
4. Carboxylic acid CH COOH
2
5. Ether CH – O – CH 3
3
6. Halo derivatives (or halides) CH Cl, C H Cl
3
2
5
Structure and Isomerism
What is isomerism
+UQOGTKUO OC[ DG FGſPGF CU HQNNQYU
Occurrence of two or more compounds having the same molecular
formula, but different structural formulae is called isomerism.

What are isomers
The compounds having the same molecular formula, but different structural
formulae are called isomers. For example, the molecular formula C H
10
4
describes the following two structural formulae: