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Acids and Alkalis

What is an acid?

When a substance dissolves in water,
the solution may be acidic, neutral or alkaline.

An acid is any substance which produces H+  ions or H3O+  ions in water.
H+  ions are called hydrogen ions, H3O+ ions are called hydroxonium ions.

You will mostly see acids in reactions as forming H+  ions.
In reality, H+ is a single proton, and does not exist on its own.
It always attaches to something, in water it joins to H2O to form H3O+ ions.

This website will use either H+(aq)  or H3O+(aq)  to mean acid in water.

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