Lesmahagow High School Science Department Acids and Bases : Summary Exercise Answers Answer the questions in your jotter. 1. What is the pH scale? acid or base is The pH number of a substance is linked to how concentrated an 2. What methods can be used to measure the pH number? Universal indicator or pH paper 3. What pH numbers are acids? pH 1-6 4. What pH numbers are bases? pH 8-14 5. What pH does a neutral solution have? pH 7 6. What is a hazard? something that can cause you danger 7. Acids and bases are both corrosive. What does this mean? A substance that burns through things 8. When universal indicator is added to a base which colour(s) will it turn? Purple/blue/dark green 9. When universal indicator is added to an acid which colour(s) will it turn? Red/orange/yellow/light green 10. Which pH is the most concentrated acid? A. pH 1 B. pH 3 C. pH 5 D.pH 6 A 11. Name a household acid Vinegar/tomato sauce/lemon juice (anything reasonable) 12. Name a household base toothpaste/dishwasher powder/bicarbonate of soda (anything reasonable) 13. Name a laboratory acid hydrochloric/nitric/sulphuric 14. Name a laboratory base sodium hydroxide/ammonia 15. An alkali is a special type of base. What is special about it? It dissolves in water 16. Acetic acid is a weak acid and has a pH value of 5. Suplhuric acid is a strong acid. Predit the pH value of sulphuric acid. A number less than 5