Why do alkalis feel soapy?

Alkalis feel soapy due to their ability to react with fats and oils on our skin, creating a slippery sensation.

Alkalis, also known as bases, are substances that can accept protons or donate pairs of electrons. When they come into contact with our skin, they react with the natural fats and oils present. This reaction is a type of saponification, which is the process of making soap. The alkali breaks down the fats and oils into glycerol and fatty acid salts, also known as soap. This soap then creates a slippery, soapy feeling on the skin.

The soapy sensation is not just a tactile experience, but also a chemical reaction happening on your skin. This is why washing your hands with soap and water is effective at removing dirt and germs. The soap, which is alkaline, reacts with the oils on your skin that may be trapping dirt or bacteria. The soap molecules have a hydrophilic (water-loving) head and a hydrophobic (water-hating) tail. The hydrophobic tail binds with the oils on your skin, while the hydrophilic head binds with the water. When you rinse your hands, the soap molecules – along with the dirt and germs – are washed away.

However, it's important to note that not all alkalis are safe to touch. Some, like sodium hydroxide, are caustic and can cause burns. The soapy feeling can be a warning sign that the substance is chemically reacting with your skin. Always handle alkalis with care, and wear appropriate protective equipment when conducting experiments.