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प्रश्न
Study and complete the following table:
| Homologous series | Alkane | Alkyne |
| General formula | CnH2n+2 | 1. ______ |
| IUPAC name | 2. ______ | Ethyne |
| Common name | Marsh gas | 3. ______ |
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उत्तर
| Homologous series | Alkane | Alkyne |
| General formula | CnH2n+2 | 1. CnH2n−2 |
| IUPAC name | 2. Methane | Ethyne |
| Common name | Marsh gas | 3. Acetylene |
Explanation:
1. The general formula of the alkyne is CnH2n−2· Due to the presence of triple bond four hydrogens are removed from the molecular formula of alkane. For example, in the case of ethyne, the two carbons have already formed triple bonds therefore they only need one more bond in order to complete their octet.
2. The IUPAC name of the first member of the alkane family is methane. Also, the common name given in the table is Marsh gas which is the common name of methane gas.
3. The common name of ethyne is acetylene as it contains the acetyl group. This name was coined by a French chemist (Marcelin-Pierre-Eugene Berthelot) in 1864.
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संबंधित प्रश्न
Write the next homologue of the following: C2H4
Write the molecular formula of two consecutive members of homologous series of aldehydes. State which part of these compounds determines their
- physical and
- chemical properties
Give the structural formula for 1, 2-dichloroethane
The molecular formula of a homologue of butane is ______.
Define homologous series of organic compounds. List its two characteristics. Write the name and formula of the first member of the series of alkenes.
The unsaturated hydrocarbons containing a carbon-carbon double bond are called _______.
Write a short note.
Homologous series
Complete the following table for the homologous series of alkanes.
| Name | Molecular formula | Condensed structural formula | Number of carbon atom | Number of -CH2- units | Boiling point °C |
| Methane | CH4 | CH4 | 1 | 1 | -162 |
| Ethane | C2H6 | CH3–CH3 | 2 | 2 | -88.5 |
| Propane | C3H8 | CH3–CH2–CH3 | 3 | 3 | -42 |
| Butane | C4H10 | CH3–CH2–CH2–CH3 | ______ | ______ | 0 |
| Pentane | C5H12 | CH3–CH2–CH2–CH2–CH3 | ______ | ______ | 36 |
| Hexane | C6H14 | CH3–CH2–CH2–CH2–CH2–CH3 | ______ | ______ | 69 |
Complete the following table for homologous series of alcohols.
| 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 |
Name the third homologue of aldehydes.
