Acids and Bases - Free Printable

Let’s work through the matching section first.

We have 15 statements (numbered 1–15) and 15 terms (lettered A–O). We need to match each statement with the correct term.

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Step-by-step matching:

1. Color litmus paper changes to when dipped in an acid
→ Acid turns litmus red → N red

2. The type of ions released in a base
→ Bases release hydroxide ions → H hydroxide

3. Color litmus paper changes to when dipped in a base
→ Base turns litmus blue → D blue

4. Different substances used to determine a base or an acid
→ These are called indicators → I indicators

5. Naturally occurring plant used as an indicator
→ China rose is a natural indicator → E China rose

6. Naturally occurring indicator orange in color
→ Turmeric is yellow-orange and changes color in base → O turmeric

7. Type of liquid that releases hydrogen ions
→ That’s an acid → B acid

8. Hydrogen and hydroxide ions are equal in this type of liquid
→ Neutral solution → L neutral

9. Litmus is made from organisms that come from alga and fungus
→ Lichens are symbiotic organisms (algae + fungus) → J lichens

10. Type of liquid that releases hydroxide ions
→ That’s a base → C base

11. The type of ions released in an acid
→ Acids release hydrogen ions → G hydrogen

12. A scale used to determine the level of acidity or base
→ pH scale → M pH

13. Found in the stomach of a person used for digestion
→ Hydrochloric acid → F hydrochloric acid

14. A Latin word that is translated to acid
→ “Acere” means sour in Latin → A acere

15. Type of paper used for measuring the acidity or base of a liquid
→ Litmus paper → K litmus

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Now let’s do the comparison section (questions 16–25). We need to circle “more” or “less” based on known pH values.

Recall approximate pH values:

- Gastric acid: ~1.5–3.5 → very acidic
- Urine: ~4.5–8.0 → can be acidic to slightly basic, but usually around 6
- Milk of Magnesia: ~10.5 → basic
- Bleach: ~12.5 → very basic
- Soapy water: ~9–10 → basic
- Ammonia: ~11–12 → very basic
- Black coffee: ~5 → acidic
- Orange juice: ~3.5–4 → acidic
- Lemon juice: ~2–2.5 → very acidic
- Sea water: ~8.1 → slightly basic
- Baking soda: ~8.3 → slightly basic

Now answer each:

16. Gastric acid is (more or less) acidic than urine.
→ Gastric acid (pH ~2) is more acidic than urine (pH ~6) → more

17. Milk of Magnesia is (more or less) basic than bleach.
→ Milk of Magnesia (pH ~10.5) is less basic than bleach (pH ~12.5) → less

18. Soapy water is (more or less) basic than ammonia.
→ Soapy water (pH ~9.5) is less basic than ammonia (pH ~11.5) → less

19. Black coffee is (more or less) acidic than orange juice.
→ Black coffee (pH ~5) is less acidic than orange juice (pH ~3.5) → less

20. Lemon juice is (more or less) acidic than orange juice.
→ Lemon juice (pH ~2) is more acidic than orange juice (pH ~3.5) → more

21. Sea water is (more or less) basic than baking soda.
→ Sea water (pH ~8.1) is less basic than baking soda (pH ~8.3) → less

22. Bleach is (more or less) basic than ammonia.
→ Bleach (pH ~12.5) is more basic than ammonia (pH ~11.5) → more

23. Gastric acid is (more or less) acidic than lemon juice.
→ Gastric acid (pH ~2) is about same or slightly more acidic than lemon juice (pH ~2.5) → more (since lower pH = more acidic)

24. Orange juice is (more or less) acidic than lemon juice.
→ Orange juice (pH ~3.5) is less acidic than lemon juice (pH ~2.5) → less

25. Baking soda is (more or less) basic than soapy water.
→ Baking soda (pH ~8.3) is more basic than soapy water (pH ~9.5? Wait — correction: soapy water is typically pH 9–10, baking soda is 8.3 → so baking soda is LESS basic) → Actually, baking soda (8.3) < soapy water (9.5) → so baking soda is less basic than soapy water.

Wait — let me double-check typical values:

- Baking soda solution: pH ~8.3
- Soapy water (dish soap): pH ~9–10 → yes, soapy water is more basic.

So: Baking soda is less basic than soapy water → less

But question says: “Baking soda is (more or less) basic than soapy water.” → Since baking soda has lower pH than soapy water, it is less basic.

✔ Confirmed.

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Final Answers:

Matching Section:

1. N
2. H
3. D
4. I
5. E
6. O
7. B
8. L
9. J
10. C
11. G
12. M
13. F
14. A
15. K

Comparison Section:

16. more
17. less
18. less
19. less
20. more
21. less
22. more
23. more
24. less
25. less

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Final Answer:
1. N, 2. H, 3. D, 4. I, 5. E, 6. O, 7. B, 8. L, 9. J, 10. C, 11. G, 12. M, 13. F, 14. A, 15. K, 16. more, 17. less, 18. less, 19. less, 20. more, 21. less, 22. more, 23. more, 24. less, 25. less