Lesson 8 CSI Acids and alkalis

Acids and Alkalis Learning objective – To be able to distinguish between acids and alkalis Success Criteria Level 5 - Identify a solution as acid or alkali using an indicator Level 4 - Give examples of indicators that can be used to classify acids and alkalis. Level 4 - Record your results on a table Level 3 - Recognise common hazard symbols. Level 3 - Be able to name some common acids

Match the meaning to the hazard symbol poisonous/toxic Corrosive irritant flammable

Names of acids Hydrochloric Citric Ethanoic acid Sulphuric Vinegar Ethanoic acid Sulphuric Phosphoric acid Nitric

Some common acids Three acids are particularly common in the laboratory . Acid Formula hydrochloric HCl sulphuric H2SO4 nitric HNO3 These are strong acids that should be treated with the greatest respect.

Indicators: acid or alkali? An indicator is a dye which changes colour according to whether it is in an acidic or alkaline solution. Litmus is an indicator that is red in acid and blue in alkali.

Litmus Test TEACHER’S NOTES Results of the litmus test are : alkali acid water

Testing using litmus Substance Colour change with red litmus Colour change with blue litmus Acid or alkali A B C