1. Ions In
Solution

2. The pH scale Hydrogen Ions make acidic solutions
Hydroxide ions make basic/alkaline solutions.
Bases are substances that can neutralise acids. They are usually metal oxides or metal hydroxides.
Alkalis are soluble bases
Alkaline
Neutral
Acid

3. Neutralisation H+ (aq) + OH-(aq) -> H2O (l)
The acid reacts with the alkali to form a salt and water which is a neutral solution. The hydrogen ions in the acid join with the hydroxide ions in the alkali to form a neutral water molecule. The gas in the acid reacts with the metal or ammonium in the alkali to form an ionic salt.
E.g.
Hydrochloric acid + sodium hydroxide -> sodium chloride +water
HCl(aq) NaOH(aq) > NaCl(aq) H20 (l)

4. Reactions of Salts Acid + Metal -> a salt + hydrogen
E.g. Sulphuric acid + potassium -> potassium sulphate + hydrogen
This is a displacement reaction
Acid + Base -> a salt + water
E.g. Sulphuric acid + sodium oxide -> sodium sulphate + water
This is a Neutralisation reaction
Acid + Alkali -> a salt + water
E.g. Sulphuric acid + potassium hydroxide -> potassium sulphate + water
This is a neutralisation reaction
Acid + Carbonate -> a salt + water + carbon dioxide
E.g. Sulphuric acid + copper carbonate -> copper sulphate + water + carbon dioxide

5. This comes from the acid
Naming Salts
type of metal or ammonium in the base/alkali/metal/carbonate which reacts with the acid
This comes from the acid
Sodium Chloride
Remember
Hydrochloric acid makes chloride salts
Sulphuric acid makes sulphates
Nitric acid makes nitrates

6. Precipitation Reactions
This is a reaction where a solid insoluble salt is produced when two soluble salt solutions are mixed together. This type of reaction is important when we want to remove heavy metal ions from polluted water.
E.g. Lead nitrate + Sodium chloride -> lead chloride + sodium nitrate
Pb(NO3)2(aq) NaCl(aq) > PbCl2(s) NaNO3(aq)
E.g.
Silver nitrate + potassium iodide -> silver iodide + potassium nitrate
AgNO3(aq) KI2(aq) > AgI(s) KNO3(aq)

7. Questions
Name the salt which is produced when hydrochloric acid reacts with ammonium hydroxide.
Which ions make acidic solutions?
What is an alkali?
Write the balanced symbol equation for sulphuric acid + potassium. Include the state symbols
What is produced in a precipitation reaction?
What is the equation for a neutralisation reaction?

8. Answers Ammonium Chloride Hydrogen Ions A soluble base
H2SO4(aq) + K(s) -> KSO4(aq) + H2(g)_
An insoluble salt
H+ (aq) + OH-(aq) -> H2O (l)