Question

What is the general formula for unsaturated fatty acids?

Answer 1

Hint: Fatty Acids are Carboxylic Acids with long aliphatic chains. These may be either saturated or unsaturated. If all the carbon -carbon bonds are single it is called saturated but if they contain double or triple bond it is called unsaturated fatty acid. These may be either linear or branched. Lipids are made up of 2 components-glycerol and fatty acid. Fatty acids are useful in making soaps, detergents and many skin care products. Soaps are Sodium and Potassium salts of fatty acids.

Complete answer:
Thus we see that if a fatty acid contains double bond or triple bond it is Unsaturated. If one double bond is present it is called mono-unsaturated fatty acid (MUFAs) and if it contains 2 or more double bonds it is called poly-unsaturated fatty acid (PUFAs).If it contain 1 or more triple bond it is called Acetylenic fatty acid.
Unsaturated fatty acids are very less stable than the saturated fatty acids and hence are more susceptible to react with reagents like water, oxygen or attack of microbes. Also the saturated fatty acids have high melting point as compared to unsaturated fatty acids since the structure is packed easily.
The general formula of unsaturated fatty acid is as- $C{H_3}{(C{H_2})_n}CH = CH{(C{H_2})_n}COOH$ where n can be any integer.
Some Examples of Unsaturated fatty acids are as follows-
Palmitoleic acid- $C{H_3}{(C{H_2})_5}CH = CH{(C{H_2})_7}COOH$
Oleic acid-$C{H_3}{(C{H_2})_7}CH = CH{(C{H_2})_7}COOH$

Note:
 Unsaturated fatty acids are highly recommended in diet as compared to saturated fatty acids since they help increase High density lipoproteins (HDL) which is called good cholesterol and decreases low density lipoproteins (LDL) which is bad cholesterol. They also help in reducing inflammation in the human body and provide a good level of energy. Olive oil is a commonly used unsaturated fatty acid.