What are the properties of lipids?

Lipids are a heterogeneous group of organic compounds that are insoluble in water and soluble in non-polar organic solvents. They have distinctive physical and chemical properties. 

General Physical Properties of Lipids

• Energy-rich organic molecules
• Soluble in non-polar solvents such as acetone, ether, chloroform, benzene, and alcohol
• Insoluble in water
• Either liquid or non-crystalline solid at room temperature
• Greasy in texture
• Hydrophobic or amphiphilic
• Devoid of ionic charges
• Present either in saturated or unsaturated structural form
• Stored in adipose tissues in the body

Chemical Properties of Lipids

• Hydrolysis of triglycerols: Triglycerides, which are neutral lipids, react with water to form carboxylic acid and alcohol in a process known as hydrolysis.
• Hydrogenation: Unsaturated fats are converted into saturated fats by hydrogenation, which involves adding hydrogen atoms. The reaction with hydrogen breaks the double bonds present in unsaturated fats, producing saturated fats. 
• Saponification: Saponification is a chemical reaction in which lipids, particularly triglycerides, react with alkalis such as sodium hydroxide (NaOH) or potassium hydroxide (KOH) to form soap or fatty acid salts of sodium or potassium, and glycerol. 
• Halogenation: When unsaturated fatty acids come into contact with halogens, halogen atoms are added to the double bonds, resulting in de-colorization, in which the halogen solution loses its original color. 

• Rancidity: Oxidation and hydrolysis of fats and oil are responsible for causing rancidity, in which the fat or oil develops a disagreeable odor.