Module 4 (C4): Acids and Bases

• Acids have a Ph of less than 7.
• Bases are the oxides and hydroxides of metals.
• soluble bases are called alkalis.
• alkalis have a Ph greater than 7.

Acids and bases (alkalis) are chemical opposites. dded together in the correct amount, they can cancel each other out.

This is called neutralisation. (PH 7)

Acid+ Base > Salt + Water

carbonates neutralise acids to produce a salt and water, but they also produce Carbon Dioxide gas. (CO2) Acid + Carbonate > Salt + Water + Carbon Dioxide

Naming Salts

The first name of a salt made by neutralisation comes from the first name of the base or carbonate used e.g.

• Sodium Hydroxide will make a Sodium salt..
• Copper Oxide will make a copper salt ..

The second name comes from the name of the acid used e.g.

• hydrochloric acid will produce a chloride salt
• sulfuric acid will produce a sulfate salt
• nitric acid will produce a nitrate salt...

Sulfuric acid- to clean metals before being painted or coated, to neutalise fertilisers & in car and motorbike batteries.

Neutrlisation can be summarised by looking at what happens to the ions in the solutions:

alkalis in solution contain hydroxide ions, OH- (aq)

acids in solution contain hydrogen ions, H+ (aq)

Acid + base > Salt + water

Therefore Neutralisation can be described as..

H+ (aq) + OH- (aq)> H2O (l)