Question

Homologous series of alcohol (till 5th)?

Answer 1

 They are ; 
1. Methanol  CH3OH
2.Ethanol   C2H5OH
3.Propanol   C3H7OH
4. Butanol  C4H9OH
5. Pentanol   C5H11OH

Answer 2

Answer: $CH_3OH$, $CH_3CH_2OH$ , $CH_3CH_2CH_2OH$ , $CH_3CH_2CH_2CH_2OH$ and $CH_3CH_2CH_2CH_2CH_2OH$

Explanation:  A homologous series is a series of compounds with the same functional group and similar chemical properties in which the members of the series differ by the number of repeating units they contain.

The functional group which represents alcohol is $OH$ and has suffix ol. Thus the five compounds of alcohols which differ by a $-CH_2$ unit are  $CH_3OH$, $CH_3CH_2OH$ , $CH_3CH_2CH_2OH$ , $CH_3CH_2CH_2CH_2OH$ and $CH_3CH_2CH_2CH_2CH_2OH$ named as methanol , ethanol, propanol, butanol and pentanol containing 1, 2 , 3 , 5 and 5 carbon atoms respectively.