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Year 8 Science — Acidic, basic and neutral substances

Sort everyday substances as acidic, basic or neutral, read what each natural indicator is telling you, and use neutralisation to explain an ant bite and a sour field.

Name: ________________________

  1. 1.Which of these did the litmus tests find to be basic?

    • a) Amla juice
    • b) Vinegar
    • c) Sugar solution
    • d) Baking soda solution

  2. 2.Red rose extract has been added to each of these three test tubes. Tap the tube holding a basic solution.

    Write the number of the part.

    123

  3. 3.Manya is blindfolded and handed two solutions to tell apart. Which kind of indicator could she still use?

    • a) Red rose extract, because it is a strong colour
    • b) Litmus paper, because the strips feel different
    • c) An olfactory indicator, whose smell changes
    • d) Turmeric paper, because turmeric is a familiar spice

  4. 4.Litmus is not made in a laboratory — it is taken from a living thing that grows on rocks and tree bark. What kind of organism is it obtained from?

  5. 5.A drop of an unknown liquid is put on turmeric paper and the yellow does not change. Which two possibilities are still open?

    • a) Nothing is open — turmeric paper settles it
    • b) It is acidic, or it is neutral
    • c) It is acidic, or it is basic
    • d) It is basic, or it is neutral

  6. 6.A substance that shows one colour in an acid and a different colour in a base has a two-word name in this chapter. What is it?

  7. 7.A basic solution is dropped onto each of these three indicators. Match each one to what it does.

    • Red litmus paper
    • Red rose extract
    • Turmeric paper
    • turns blue
    • turns green
    • turns red

  8. 8.Each of these was tested with blue and red litmus paper. Sort them by the nature the papers reported.

    Groups: Acidic · Basic · Neutral

    • Soap solution
    • Tamarind water
    • Lemon juice
    • Sugar solution
    • Washing powder solution
    • Vinegar
    • Salt solution
    • Lime water

Answer key — Year 8 Science — Acidic, basic and neutral substances

  1. 1. d) Baking soda solution
  2. 2. 2 — Basic
  3. 3. c) An olfactory indicator, whose smell changes
  4. 4.
    • lichens
    • lichen
  5. 5. b) It is acidic, or it is neutral
  6. 6.
    • acid-base indicator
    • acid base indicator
    • indicator
  7. 7. Red litmus paper → turns blue; Red rose extract → turns green; Turmeric paper → turns red
  8. 8. Lemon juice → Acidic; Tamarind water → Acidic; Vinegar → Acidic; Soap solution → Basic; Lime water → Basic; Washing powder solution → Basic; Sugar solution → Neutral; Salt solution → Neutral