Base
BAYS
/beɪs/
A chemical substance that neutralizes acids, typically accepts protons, and turns litmus blue; typically, a liquid with a pH of more than 7.
Chemically, bases are defined by their ability to accept protons (Brønsted-Lowry) or donate electron pairs (Lewis). Colloquially, it refers to the opposite of an acid.
The story behind the word. The chemical term 'base' comes from the Greek word 'basis,' meaning 'a step, a foundation, a pedestal.' This term was introduced into chemistry by the French chemist Guillaume-François Rouelle in the mid-18th century. He used it to describe substances that served as a 'base' or 'foundation' for salts, as they reacted with acids to form salts.
Word relationships
- Alkali: A specific type of strong, soluble base, typically of an alkali metal.
- Acid: A chemical substance that neutralizes bases, donates protons, and has a pH less than 7.
- Acidic: Having the properties of an acid.
Commonly confused with
- Acid: An 'acid' donates protons and has a pH below 7; a 'base' accepts protons and has a pH above 7.
Word family
- basic (adjective): Having the properties of a base; fundamental.
- basicity (noun): The quality or state of being basic.
Collocations
- strong base
- weak base
- alkali base
- acid-base reaction
- nitrogenous base
Idioms & expressions
- off base
- touch base
Example sentences
- "Baking soda, or sodium bicarbonate, is a mild base often used to neutralize stomach acid." Baking soda is a common base.
- "The strong base sodium hydroxide is highly corrosive and must be handled with extreme care." Bases react with acids.
Memory hook
Think of a 'base' as the 'foundation' (basis) that an acid reacts with to build a salt. Foundation for salts
When not to use
Do not use 'base' in a chemical context if you mean a foundation or a starting point, unless you are making a deliberate pun.
Fun facts
- The definition of acids and bases has evolved over time, with Arrhenius, Brønsted-Lowry, and Lewis each contributing broader theories.
- Many common cleaning products, like bleach and ammonia, are basic solutions.
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