Soap is formed by the reaction of a fatty acid with an alkali metal, such as sodium or potassium. The fatty acids commonly used in soap making are stearic acid, oleic acid, and palmitic acid. These fatty acids have a carboxyl group (COOH) at one end, which reacts with the alkali metal to form a salt. This process is known as saponification.
Option 1 states that soap is the sodium or potassium salt of stearic acid. Stearic acid is a common fatty acid found in many natural fats and oils, and it can be used to make soap.
Option 2 states that soap is the sodium or potassium salt of oleic acid. Oleic acid is another fatty acid commonly found in natural fats and oils, such as olive oil. It can also be used to make soap.
Option 3 states that soap is the sodium or potassium salt of palmitic acid. Palmitic acid is yet another fatty acid found in natural fats and oils, and it is frequently used in soap making.
Option 4 correctly states that soap can be made from any of the mentioned fatty acids. Hence, the correct answer is option 4 - "All of the above."