Success Homeschool

Year 9 Science · Acids and bases

Name: ______________________

Date: ____________

1. A solution has a pH of 3. It is…
- ☐ (a) Strongly basic
- ☐ (b) Neutral
- ☐ (c) Acidic
- ☐ (d) Weakly basic
2. Which of these is a base?
- ☐ (a) Vinegar
- ☐ (b) Lemon juice
- ☐ (c) Orange juice
- ☐ (d) Bicarbonate of soda solution
3. What are the products of neutralisation between an acid and a hydroxide base?
- ☐ (a) Salt and water
- ☐ (b) Oxygen and water
- ☐ (c) Acid and base
- ☐ (d) Sugar and carbon dioxide
4. Why do some Australian farmers spread lime on paddocks?
- ☐ (a) To make the soil more acidic
- ☐ (b) To raise the pH of acidic soil
- ☐ (c) To kill all soil organisms
- ☐ (d) To make the soil white
5. How many times more acidic is pH 2 than pH 3?
- ☐ (a) 2 times
- ☐ (b) 10 times
- ☐ (c) 100 times
- ☐ (d) Exactly the same
6. What is the pH of a neutral solution at 25 °C? (number)
7. What colour does red cabbage indicator usually turn in vinegar?
8. A substance that changes colour depending on pH is called an i________.

Answer sheet

1. Acidic — Any pH below 7 is acidic.
2. Bicarbonate of soda solution — Bicarbonate of soda dissolves to form a weakly basic solution.
3. Salt and water — Acid + base → salt + water.
4. To raise the pH of acidic soil — Lime is basic and neutralises acidic soils.
5. 10 times — Each pH unit is a tenfold change.
6. 7 — Neutral is pH 7 at 25 °C.
7. pink — In acids, red cabbage indicator turns red or pink.
8. indicator — This is an indicator.