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.