Chapter U2, Problem 2RE

Interpretation Introduction

Interpretation: The structure of two isomers having formula ${\text{C}}_{\text{2}}{\text{H}}_{\text{4}}\text{O}$ should be drawn.

Concept Introduction: Molecules that differ in the arrangement of atoms in the space but have same molecular formula are said to be isomers. In structural isomers, the arrangement of atoms in the molecule is different.

Answer to Problem 2RE

The structure of two isomers having formula ${\text{C}}_{\text{2}}{\text{H}}_{\text{4}}\text{O}$ is:

  

  

Explanation of Solution

To draw the isomers of given formula ${\text{C}}_{\text{2}}{\text{H}}_{\text{4}}\text{O}$ , the degree of unsaturation is calculated in order to determine the total number of $\text{π}$ bonds or rings in the structure. The formula to determine the degree of unsaturation is:

  $\text{degree of unsaturation = }\frac{\text{2C + 2 + N - H - X}}{2}$

Where C represents number of carbon atoms, N represents number of nitrogen atoms, H represents number of hydrogen atoms and X represents number of halogens.

So, the degree of unsaturation for the given compound is calculated as:

  $\begin{array}{l}\text{degree of unsaturation = }\frac{\text{2(2) + 2 + 0 - 4 - 0}}{2}\\ \text{degree of unsaturation = }\frac{\text{6 - 4}}{2}\\ \text{degree of unsaturation = 1}\end{array}$

Since degree of unsaturation is one so, it represents that there is one $\text{π}$ bond or one ring in the structure that means the structure is unsaturated.

Thus, the structures will be:

Containing one $\text{π}$ bond:

  

  

Containing ring: