Science
What is a Base (Chemistry)?
In chemistry, a base is a substance that accepts hydrogen ions or releases hydroxide ions (OH⁻) in water, giving it a pH above 7 and often a slippery feel. Bases are the chemical opposite of acids, and the two neutralize each other to form water and a salt.
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Watch a 2-minute lesson with voice + animation that explains a base (chemistry).
Key things to understand
- 1A base releases hydroxide ions (OH⁻) in water, or accepts hydrogen ions from an acid.
- 2Bases have a pH above 7 — the higher the pH, the stronger the base.
- 3They often feel slippery and taste bitter (think soap or baking soda).
- 4A base and an acid neutralize each other, producing water and a salt.
- 5Strong bases (like sodium hydroxide) are highly corrosive; mild ones (like baking soda) are everyday and safe.
Frequently asked questions
- What's the difference between a base and an acid?
- Acids release hydrogen ions and have a pH below 7; bases release hydroxide ions (or accept hydrogen ions) and have a pH above 7. Mixed together, they neutralize each other.
- Is a base the same as an alkali?
- An alkali is a base that dissolves in water. All alkalis are bases, but some bases don't dissolve well, so not every base is called an alkali.
- What are everyday examples of bases?
- Baking soda, soap, ammonia-based cleaners, and antacids are all bases — which is why antacids relieve acidic stomach upset by neutralizing acid.