What substances are acids and what are bases?
I’ve heard this question asked too many times in class so I think we have to look at the different
substances which are acids and bases
Acids produce hydrogen ions (H+) in solution. This is a positively charged ion of hydrogen
Bases produce hydroxide ions (OH-) in solution. This is a negatively charged ion with 1 oxygen and 1
hydrogen bound together.
Acids
There are several things which tell you a
substance is an acid. First their names usually
end in “acid”. For example hydrochloric acid and
nitric acid.
Second, the chemical formula always contains a
hydrogen or many hydrogens and the acidic
hydrogen is usually separate from the others.
For example Ethanoic acid has a chemical
formula CH3COOH
Strong and weak acids
There are only 3 strong acids
Hydrochloric acid (HCl), Sulfuric Acid (H2SO4) and Nitric acid (HNO3). All the others are weak acids.
Bases
Strong bases
Strong bases are either Metal hydroxides or Metal oxides. You will
only need to know about the metal hydroxides for the test. Metal
hydroxides can be identified by having a metal and a hydroxide
molecule (OH)
Weak Bases
Weak bases are either Metal Carbonates or Metal HydrogenCarbonates. These have the carbonate molecule (CO3) or Hydrogencarbonate molecule (HCO3) attached to a metal. The carbonate and
hydrogen carbonate
molecule react with water
in solution to produce a
small amount of hydroxide
ions. That is why they are
called bases.