Flipped 4: Neutralisation
A chemical reaction happens if you mix together an acid and a base. The reaction is called neutralisation, and a neutral solution is made if you add just the right amount of acid and base together.
Metal Oxides & Metal Hydroxides
Metal oxides and metal hydroxides are two types of bases (alkali). For example copper oxide and sodium hydroxide.
Here are general word equations for what happens in their neutralisation reactions with acids.
metal oxide + acid → a salt + water
metal hydroxide + acid → a salt + water
Notice that a salt and water are always produced. The mixture usually warms up a little during the reaction, too. The exact salt made depends upon which acid and base were used.
When is neutralisation useful?
- Farmers use lime (calcium oxide) to neutralise acid soils.
- Your stomach contains hydrochloric acid, and too much of this causes indigestion. Antacid tablets contain bases such as magnesium hydroxide and magnesium carbonate to neutralise the extra acid.
- Bee stings are acidic. They can be neutralised using baking powder, which contains sodium hydrogen carbonate.