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प्रश्न
Write a short note.
Homologous series
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उत्तर
- The series of carbon compounds formed by joining the same functional group in the place of a particular hydrogen atom on the carbon chains having sequentially increasing length is called homologous series.
- There are different homologous series in accordance with the functional group. For example, homologous series of alcohols, homologous series of carboxylic acids, homologous series of aldehydes, etc.
- All the members of the homologous series are homologues of each other and they can be represented by the same general molecular formula.
- Physical properties generally show a gradual change with the increase in molecular mass in the series whereas chemical properties of the members of the series show similarity because of the presence of the same functional group in them.
APPEARS IN
संबंधित प्रश्न
Classify the following carbon compounds into two homologous series and name them.
C3H4, C3H6, C4H6, C4H8, C5H8, C5H10
Write the name and formula of the 2nd member of homologous series having general formula CnH2n + 2.
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
Write the molecular formula of first two members of homologous series having functional group −Br.
Write the molecular formula of first two members of homologous series having functional group – OH
Complete the following table which relates to the homologous series of hydrocarbons.
|
General Formula |
IUPAC name of the homologous series | Characteristic bond type | IUPAC name of the first member of the series |
| `C_nH_(2n-2)` | (A)________ | (B)______ | (C)______ |
| C_nH_(2n+1) | (B)________ | (E)______ | (F)______ |
Carbon compounds have usually ______ melting points and boiling points because they are ______ in nature.
Give the molecular formula of one homologue of the following:
C3H6
Give the name and structural formula of one homologue of the following:
CH3OH
Give the abbreviated formula of the third member of the alcohol.
Give the structure of the second member of the alcohol group.
Distinguish between homologous organs and analogous organs. In which category would you place wings of a bird and wings of a bat? Justify your answer giving a suitable reason.
Give the names of the first four members of the homologous series of
alkynes.
Haloalkanes react with alkalies to produce alcohol. Give the equation for the preparation of the second member of the homologous series of alcohol. State under what condition the reaction occurs.
Assertion (A): In a homologous series of alcohols, the formula for the second member is C2H5OH and the third member is C3H7OH.
Reason (R): The difference between the molecular masses of the two consecutive members of a homologous series is 144.
Cyclohexane : Cyclic hydrocarbon : : Isobutylene : _______
As one ascends in any homologous series, physical properties change gradually.
Define a homologous series.
Name and draw the electron dot structure of first homologue of alkynes series.
