2. Quiz on acids and alkalis
01/04/12
Acid, alkali or both???
• This a pH of less than 7
• This could kill cells
• This is often used in cleaners or soap
• This would turn Universal Indicator red
• Sodium hydroxide is a common ____________
• This would feel soapy on your skin
• This could be a corrosive
• This will turn universal indicator purple
• This would taste sour
• Lemon juice and vinegar are examples of weak _____
3. Hazard signs to learn…
01/04/12
Acid Corrosive
h i
Harmful Irritant
4. Universal Indicator and the pH scale
01/04/12
Universal Indicator is a mixture of liquids that will produce a
range of colours to show how strong the acid or alkali is:
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Stomach acid Lemon juice Water Soap Baking powder Oven cleaner
Strong acid Strong alkali
Neutral
5. Neutralisation
01/04/12
An acid and alkali will neutralise each other (if the correct
amounts are used:
Acid + alkali Salt + water
E.g. hydrochloric acid + sodium hydroxide sodium chloride + water
6. Useful acid-alkali reactions
01/04/12
1) Hydrochloric acid is used in the stomach
to help _______. If we eat too many “rich”
foods our stomachs create too much ____ –
this is called ______. This acid needs to be
neutralised by taking indigestion tablets.
2) Soil is naturally acidic, mainly due to acid ____. This can
have bad effects on ____ and vegetable growth, so the
excess acid may need to be neutralised with an _____ or
suitable fertiliser.
Words – plant, digestion, indigestion, alkali, rain, acid
