What is a key characteristic of bases?

A key characteristic of bases is that they feel slippery. This slippery texture is due to the interaction of bases with fats and oils, a property that can be attributed to the presence of hydroxide ions. When bases come into contact with skin or other surfaces, they can form a kind of soap-like feel, which is often used to identify them in a laboratory setting.

This property of feeling slippery distinguishes bases from acids, which are known for their sour taste and the ability to turn blue litmus paper red, indicating a change in pH. Additionally, while some bases may react with certain metals, this is not a universal characteristic of all bases.