Reactions of Acids
Science: KS3, topic 2.2.4
Reactions of Acids
When an acid and alkali are mixed together, they react to make a salt and water. Metals react with acids to make salt and hydrogen gas.
Neutralisation reactions
- A neutralisation reaction is a reaction between an acid and alkali to make water and a salt.
- This is called a neutralisation reaction because water is neutral.
- The salt is often dissolved into the solution, so cannot be seen initially.
- When writing the word equations for acids reacting with alkalis, you need to work out the name of the salt produced.
- The ending of the salt is given by the acid.
Naming products
- Hydrochloric acid always makes something-chloride.
- Sulfuric acid always makes something-sulfate.
- Nitric acid always makes something-nitrate.
- The first part of the salt name is the metal from the alkali.
- The alkali can be any metal with ‘oxide’ or ‘hydroxide’ at the end.
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Examples of neutralisation reactions
- Sulfuric acid + magnesium hydroxide → magnesium sulfate + water
- Hydrochloric acid + potassium oxide → potassium chloride + water
- Nitric acid + calcium hydroxide → calcium nitrate + water
- Sulfuric acid + strontium hydroxide → strontium sulfate + water
Metals and acids
- The general equation for the reaction between a metal and an acid is:
- Metal + acid → salt + hydrogen
- When a metal is mixed with an acid, you will see bubbles being produced.
- The bubbles are hydrogen gas.
- The solution made contains salt dissolved in it.
- The first part of the salt name is the metal.
- The ending of the salt name comes from the acid (as with the neutralisation reactions).
Examples of metals reacting with acids
- Magnesium + hydrochloric acid → magnesium chloride + hydrogen
- Potassium + hydrochloric acid → potassium chloride + hydrogen
- Calcium + nitric acid → calcium nitrate + hydrogen
- Strontium + sulfuric acid → strontium sulfate + hydrogen
Test yourself on Reactions of Acids
Which of these is NOT a neutralisation reaction?
Strontium is added to dilute hydrochloric acid. What would happen?
What is formed when nitric acid reacts with calcium hydroxide?
Which of these is true of reactions with acids?