Propenoic acid is an unsaturated carboxylic acid. Describe how you could show

that it is an unsaturated compound giving details of the test and the result.

Tests for unsaturation involves addition across the multiple bonds in the unsaturated compound.

Explanation:

In organic chemistry, we define an unsaturated compound as any compound that contains a double or triple bond. These multiple bonds are also known as pi bonds.

There are two major tests for unsaturation which shall both be discussed here.

The first test for unsaturation is by the use of bromine water. The unknown sample is passed through a solution of bromine water which normally appears reddish brown. The bromine water becomes decolorized due to addition of bromine across the multiple bond. This is a standard test for unsaturation.

Secondly, unsaturated compounds decoulourize a solution of potassium permanganate when passed through it. This alone can not be used as a distinctive test for unsaturation.

Propenoic acid will give a positive test to the both reagents showing that it contains multiple bonds, in this particular instance, a double bond.