Here's why:

* Acids are typically sour-tasting, not bitter. Think of the taste of lemon juice or vinegar, which are both acidic.

* Acids are not slippery. They are often corrosive and can cause burns.

* Slippery substances are often associated with bases (alkalines), which are the chemical opposite of acids. For example, soap is slippery because it's basic.

In summary: Acids are typically sour-tasting and corrosive, while slippery substances are usually associated with bases.