Vinegar, orange juice, and battery fluid are familiar acids. Different acids have different acid strengths.
Some characteristics of acids are:
- They can react with certain metals, such as magnesium and zinc, to produce hydrogen gas.
- They can neutralize bases. This reaction is called aneutralization reaction.
- Acids can change the color of blue litmus to red. Litmus is a kind of pH-sensitive dye. It is therefore used as an acid-base indicator.
The three most important definitions for acids follow:
- Arrhenius definition: Acids produce H+ ions in aqueous solutions.
- Bronsted-Lowry definition: Acids are hydrogen-ion donors.
- Lewis definition: Acids are electron pair acceptors.