Q8 of 48 Page 1

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.

The series which consists of similar structures and similar chemical properties in which the successive compounds differs by a CH2 group is termed as homologous series.

The two consecutive members of homologous series are:


1. Methane CH4


2. Ethane C2H6


The members of the homologous series consist of same general formula such as Alkanes have general formula CnH2n+2 and the two adjacent homologues have a difference of molecular mass of 14 u. Therefore, the members of the homologous series shows a change in the physical properties with increase in the molecular mass.


Since the structure of the compounds of homologous series is similar, so they have similar chemical properties.


More from this chapter

All 48 →
6

We often observe domestic waste decomposing in the by lanes of residential colonies. Suggest ways to make people realize that the improper disposal of waste is harmful to the environment.

 7

Write the name and the structural formula of the compound formed when ethanol is heated at 443 K with excess of cone. H2SO4. State the role of conc. H2SO4 in this reaction. Write chemical equation for the reaction.

 9

Given below are some elements of the modern periodic table:

4 Be, 9 Fe, 14 Si, 19 K, 20 Ca


(i) Select the element that has one electron in the outermost shell and write its electronic configuration.


(ii) Select two elements that belong to the same group. Give reason for your answer.


(iii) Select two elements that belong to the same period. Which one of the two has bigger atomic size?


 10

Write the number of periods the modem periodic table has. How do the valency and metallic character of elements vary on moving from left to right in a period? How do the valency and atomic size of elements vary down a group?