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प्रश्न
State any four characteristics of a homologous series
State two characteristics of a homologous series.
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उत्तर
Characteristics of a homologous series:
- Each member of the series differs from the preceding one by the addition of a -CH2 group and by 14 a.m.u.
- All members of a homologous series share the general formula.
Example: The general formula for alkane is CnH2n+2 and alkene is CnH2n. - The physical properties of the members show a gradation in properties as the molecular mass increases.
- The chemical properties also show a gradient similarity.
Example: Methane and ethane react with chlorine to form methyl chloride and ethyl chloride, respectively.
CH4 + Cl2 → CH3Cl
C2H6 + Cl2 → C2H5Cl - All members of a homologous series can be prepared by the same general method of preparation.
Example: Alcohols can be prepared from alkyl halides.
`CH_3Br+KOH " Boil"/""CH_3OH+KBr`
`C_2H_5Br+KOH " Boil"/""C_2H_5OH+KBr`
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संबंधित प्रश्न
Write the next homologue of the following: C2H4
What is meant by homologous series of carbon compounds?
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 -Cl.
Write the molecular formula of the 2nd and 3rd member of the homologous series where the first member is ethyne.
Fill in the following blank with suitable word:
Carbon compounds have usually ... melting points and boiling points because they are ...... in nature.
Give the molecular formula of one homologue of each of the following:
C2H6
What is a homologous series? Explain with an example.
An organic compound having the molecular formula C3H6O can exist in the form of two isomers A and B having different functional groups. The isomer A is a liquid which is used as a solvent for nail polish. The isomer B is also a liquid. An aqueous solution of one of the lower homologues of B is used for preserving biological specimens in the laboratory
(a) What is compound A?
(b) Write the electron-dot structure of A.
(c) What is compound B?
(d) Write the electron-dot structure of B.
(e) Name the lower homologue of compound B which is used in preserving biological specimens.
Succeeding members of a homologous series differ by ______.
Define homologous series of organic compounds. List its two characteristics. Write the name and formula of the first member of the series of alkenes.
What is the difference in the molecular formula of any two adjacent homologues:
(i) In terms of molecular mass
(ii) In terms of number and kind of atoms per molecule?
The general formula of Alkane is _________________
As one ascends in any homologous series, physical properties change gradually.
Which of the following does not belong to the same homologous series?
Name the following organic compound:
The first homologue whose general formula is CnH2n.
Name the third homologue of aldehydes.
