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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 molecular formula of the 2nd and 3rd member of the homologous series where the first member is ethyne.
Give the molecular formula of one homologue of the following:
C3H6
The molecular formula of an organic compound is C18H36. Name its homologous series.
The molecular formula of a homologue of butane is:
(a) C4H8
(b) C3H6
(c) C4H6
(d) C3H8
Why homologous series of carbon compounds are so called? Write chemical formula of two consecutive members of a homologous series and state the part of these compounds that determines their (i) physical properties, and (ii) chemical properties.
Study the different conclusions drawn by students of a class on the basis of observations of preserved/available specimens of plants and animals.
I. Potato and sweet potato are analogous organs in plants.
II. Wings of insects and wings of birds are homologous organs in animals.
III. Wings of insects and wings of bats are analogous organs in animals.
IV. Thorns of citrus and tendrils of cucurbita are analogous organs in plants.
The correct conclusions are:
(A) I, and II
(B) II and IV
(C) I and III
(D) III and IV
Give the names of the first four members of the homologous series of
alkynes.
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 |
Successive members of a homologous series vary by how many atomic mass unit?
Consider the following molecular formulae of carbon compounds:
(i) CH3COOH (ii) CH3OH (iii) C2H6 (iv) C3H4 (v) C4H8
- Which one of these compounds belongs to homologous series of alcohols?
- Identify the compound having triple bond between carbon-carbon atoms.
- Write the molecular formula of the first member of the homologous series to which CH3COOH belongs.
- Write the general formula of the series to which the compound C4H8 belongs.
