Key Concept: pH values from 0 to 14 describe acidity and alkalinity. Low pH is acidic, high pH is alkaline, 7 is neutral.
Section A: Classifying Solutions
1. Classify each pH value as acidic, neutral or alkaline: 2, 7, 9, 13. [4]
2. Which is more acidic, pH 1 or pH 4? Explain briefly. [2]
3. Give one example of a strong acid and one example of a weak acid. [2]
Section B: Using pH Values
4. A solution has pH 11. Is it strongly or weakly alkaline? [1]
5. Match each substance to a suitable pH value: stomach acid, distilled water, soapy water. [3]
Total marks: 12
Mark Scheme
1. 2 acidic, 7 neutral, 9 alkaline, 13 alkaline [4]
2. pH 1; lower pH means more acidic [2]
3. Strong acid: hydrochloric or sulfuric; weak acid: ethanoic or carbonic [2]
4. Strongly alkaline [1]
5. Stomach acid pH 1-2; distilled water pH 7; soapy water pH 10-12 [3]