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Question
What is a homologous series? Explain with an example.
Solution
- A group of compounds having similar structures and chemical properties but their successive compounds differ by a CH2 group is called a homologous series.
- Example: Alkanes have similar structures and similar chemical properties, so they can be grouped together to form a homologous series. The general formula of the homologous series of alkanes is CnH2n+2, where n is the number of carbon atoms in each molecule.
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RELATED QUESTIONS
State any four characteristics of a homologous series
What is meant by homologous series of carbon compounds?
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(c) six
(d) seven
What is homologous series ?
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| General formula | CnH2n | CnH2n-2 | CnH2n+2 |
| IUPAC name of the homologus series | |||
| Characteristic bond type | Single bonds | ||
| IUPAC name of the first member of the series | |||
| Type of reaction with chlorine | Addition |
The unsaturated hydrocarbons containing a carbon-carbon double bond are called _______.
The phenomenon in which compounds having different structural formulae have the same molecular formula is called _______.
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| Name | Molecular formula | Condensed structural formula | Number of carbon atom | Number of -CH2- units | Boiling point °C |
| Methanol | CH4O | CH3-OH | 1 | 1 | 63 |
| Ethanol | C2H6O | CH3–CH2-OH | 2 | 2 | 78 |
| Propanol | C3H8O | CH3–CH2–CH2-OH | ______ | ______ | 97 |
| Butanol | C4H10O | CH3–CH2–CH2–CH2–OH | ______ | ______ | 118 |
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Which of the following does not belong to the same homologous series?
Which of the following does not belong to the same homologous series?
Study and complete the following table:
| Homologous series | Alkane | Alkyne |
| General formula | CnH2n+2 | 1. ______ |
| IUPAC name | 2. ______ | Ethyne |
| Common name | Marsh gas | 3. ______ |
