Chapter 23, Problem 28PS

Interpretation Introduction

Interpretation: The structures for the seven isomers which have molecular formula ${\text{C}}_{\text{3}}{\text{H}}_4{\text{Cl}}_2$ has to be drawn. The systematic name for each isomer has to be written.

Concept introduction:

Alkenes are the hydrocarbons which have a genral molecular formula ${\text{C}}_{\text{n}}{\text{H}}_{\text{2n}}$. Alkenes are consist of double bond (one pi bond) due to which they are known as unsaturated hydrocarbons. Alkenes can show two type of isomerism,(1) Geometrical Isomerism (2) Structural Isomerism.

(1) Geometrical Isomerism: This type of isomerism in case of alkenes is known as cis-trans isomerism. When two same group or have similar priority present opposite side of double bond then isomer is known as trans isomer, and if both are present same side of the double bond then isomer is called as cis isomer.

(2) Structural Isomerism: Structural Isomers are the structure of a molecule with same molecular formula but have different arrangements of bonds and atoms and position of double bond also changes from more substituted to less substituted or vice-versa.

The systematic name has $\text{-ene}$ in the suffix of the parent name of the longest carbon atoms chain.