- 1 Homologous series thiab cov yam ntxwv ntawm homologous series
- 2 Homologous series of Alkanes, Alkenes, and Alkynes
Homologous series thiab cov yam ntxwv ntawm homologous series
Series of organic compounds which have a same functional group, similar structural feature but differ from each other by an integer number of CH2 (methylene group) is called “Homologous series”. The number of homologous series differs by molecular mass 14.
Characteristics of Homologous series:
- All numbers of homologous series have similar structures.
- Physical properties of homologous series change progressively more than or less than with the number of carbon atoms.
- The members of homologous series are represented by same general formula CnH2n+2 for the alkane, CnH2n for alkene and CnH2n-2 for alkyne.
- The molecular formula difference between any two consecutive members is CH2.
- The molecular weight differences between any two successive members are 14.
- The various members of homologous series have the same general method of preparation.for example all alkanes can be prepared by the reduction of alkyl halide.
- The various members of homologous series show regular graduations in physical properties and have same chemical properties.
- The name of the member of a homologous series either end with the same suffix or start with the same prefix.
Homologous series of Alkanes, Alkenes, and Alkynes
Homologous series is a group of compounds with same general formula, listed in order to increase in size, it is hydrocarbon chain with differing in structure, each structure differs only by CH2 in each unit. They have similar chemical properties.
Generally, there are three Homologues series which can be discussed further…
ALCOHOL: CnH2n+1 OH
The first Homologous series is Alkanes, it contains ane at the end of the name of each member of Alkane. Its general formula is and chemically it is not soluble in water.
- CH3-OH, CH3-CH2-OH, C3H7-OH.
- CH3-COOH, CH3-CH2-COOH, C3H7
- CH3-O-CH3, C2H5-O-CH3, C3H7-O-CH3
The names of member of Alkanes are as follows:
Alkenes are the second Homologous series and the name of the Alkenes family members end up with one.
Alkenes are much reactive than Alkanes family because Alkenes has double bond Carbon to Carbon. Its general formula.
The names of the members of Alkenes are as follow:
|Straight-chain||CnH2n + 2 (n ≥ 1)||H3C− … −CH3|
|Straight||2 (n ≥ 1)||−CF2−||−CF3|
|Chain alkyl||CnH2n + 1 (n ≥ 1)||−CH2−||H3C−|
|Straight-chain 1-alkenes||CnH2n (n ≥ 2)||−CH2−||H2C=C− … −CH3|
|Cycloalkanes||CnH2n (n ≥ 2)||−CH2−|
|Chain 1-alkynes||CnH2n − 2 (n ≥ 2)||−CH2−||HC≡C− … −CH3|
|Straight primary alcohols||CnH2n + 1OH||−CH2−||H3C− … −OH|
|Straight-chain primary acids||CnH2n +3 (n ≥ 0)||−CH2−||H3C−|
|Straight azanes||NnHn + 2 (n ≥ 1)||−NH−||H2N− … −NH2|
Alkynes are the third Homologous series and the name of the alkynes family member ends up with ‘yne’. It contains triple Carbon to Carbon bonding and it’s general formula.
The names of Alkynes family member are as follow:
Vam tias koj zoo nkaus li qhov tsab xov xwm no, Yog hais tias koj yeej nco ntsoov koj muab ib thumbs tuaj thiab ib tug zoo saib nram qab no.