Acids, Bases and the pH Scale

Try these questions

5 questions from this lesson’s quiz. Start the lesson to answer them and see the right answers.

1. 1. A pupil adds red cabbage indicator to a solution made from wood ash and water. What colour is the indicator most likely to turn?

   • A. Reddish-pink
   • B. Green or yellow
   • C. Colourless
   • D. Bright red

2. 2. In an investigation to test soil acidity, pupils shake the soil sample with distilled water instead of tap water. Why?

   • A. Tap water is too cold to dissolve the soil
   • B. Distilled water makes the soil turn neutral
   • C. Tap water often contains dissolved minerals that can change the pH reading
   • D. Distilled water is acidic and helps the indicator work

3. 3. A river has a pH of 6. After acidic effluent is released into it, the pH falls to 4. How many times greater is the hydrogen ion concentration at pH 4 than at pH 6? (Each 1 unit change in pH is a ten-fold change.)

   Type your answer (in times) in the lesson.

4. 4. Name the substance that farmers in Kenya apply to acidic soil to raise its pH.

   Type your answer in the lesson.

5. 5. Why is baking soda applied to a bee sting to relieve the pain?

   • A. Baking soda is a mild base that neutralises the acidic sting
   • B. Baking soda is a strong acid that burns the venom
   • C. Baking soda is neutral and washes the sting away
   • D. Baking soda is an indicator that shows the venom's pH

More in Introduction to Integrated Science

• ▸Classification of Mixtures and Purity Determination
• ▸Physical Separation Techniques for Mixtures
• ▸Community Service Learning Water Purification Project
• ▸Acids, Bases, and Natural Indicators
• ▸Introduction to Laboratory Safety and Rules
• ▸Laboratory Design, Layout, and Safety Installations
• ▸Chemical Hazard Symbols
• ▸Chemical Hazard Symbols

See every Grade 7 Integrated Science lesson →