Starter: Describe in detail how we can we test to see if a liquid is an acid or an alkali? Extension: Explain the difference between a base and an alkali. Give one example. Starter: Describe in detail how we can we test to see if a liquid is an acid or an alkali? Extension: Explain the difference between a base and an alkali. Give one example.

Starter: Describe in detail how we can we test to see if a liquid is an acid or an alkali? Extension: Explain the difference between a base and an alkali. Give one example. Starter: Describe in detail how we can we test to see if a liquid is an acid or an alkali? Extension: Explain the difference between a base and an alkali. Give one example.

Applying practical skills to make an indicator Starter: Describe in detail how we can we test to see if a liquid is an acid or an alkali? Extension: Explain the difference between a base and an alkali. Give one example.

Making an indicator Task: You will be given a variety of liquids. You have to test to see if they are acidic or alkaline using an indicator that you have made using…

Work Card Red Cabbage Indicator Apparatus: Red cabbage, 100ml beaker, filter funnel, filter paper, conical flask, 70ml water, Bunsen, tripod, mat Method: 1) Collect the above apparatus. 2) Place the red cabbage in your 100ml beaker. Add 70ml hot water. 3) Heat the beaker until the water boils and gets purple. While you are waiting for the indicator to cool down, answer to the questions about last practical work. 4) Remove from tripod and filter the solution into a conical flask. Safety: Take care when removing the beaker from the tripod as it will be very hot. See your teacher for guidance

1) Boil the red cabbage with 50 ml water 2) Filter and collect the filtrate

Testing Unknown liquids 1) Once you have made your indicator you will be given a variety of acids and alkalis. 2) Test to see what the pH of the liquids are. Record your results in a suitable table

Results LiquidpHAcid or Alkali Lemon juice Coke Ammonia Sodium hydroxide Vinegar Hydrochloric acid Bleach

Homework Collect a piece of pH paper and test a variety of household liquids. Suggestions: Cleaning fluid, shampoo, toothpaste, orange Juice, vinegar etc.