Many substances are acidic or basic. Concentrated acids and bases are corrosive so it is important to be able to identify them.
Corrosive - can damage substances it comes into contact with.
Acids and Bases in everyday life
Acids
- Lemons - citric acid
- Grapes - tartaric acid
- Apples - malic acid
- Vinegar - acetic acid
- Acid drop sweets - citric acid
- Fizzy drinks - carbonic acid
- Stomach - hydrochloric acid
- Vitamin C - absorbing acid
Bases
- Indigestion tablets - magnesium hydroxide
- Window cleaner - ammonia solution
- Toothpaste - sodium hydrogen carbonate
- Drain cleaner - sodium hydroxide
Litmus paper
Litmus paper is used to see if a solution is acidic or basic.
Acids turn blue litmus paper red.
Bases turn red litmus paper blue.
The pH scale
The pH scale is used to indicate exactly how acidic or basic a substance is.
The pH scale goes from 0 - 14
Indicator - A substance which, by changing colour, can show whether another substance is an acid or a base.