Exercise Question Answers for Chapter 1- Natural Resources and Their Use for class 8 Subject Social Science ************************************** Questions and Activities: 1. What can make what is today a renewable resource non-renewable tomorrow? Describe some actions that can prevent this from happening. Answer: Overuse of a renewable resource can make it scarce and non-renewable. Pollution can damage natural resources and reduce their ability to renew. Deforestation can reduce the number of trees which take a long time to grow again. Water sources can dry up if used faster than they are refilled. Climate change can affect the natural cycle of renewal. To prevent this, we must use resources wisely, recycle, and protect nature. 2. Name five ecosystem functions that serve humans. Answer: Forests provide clean air by absorbing carbon dioxide. Wetlands purify water by filtering waste. Bees and insects help in pollination for growing crops. Trees ...
Multiple Choice Questions Chapter 2- Exploring Substances: Acidic, Basic, and Neutral Subject Science
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1. What does blue litmus paper turn into when it touches an acid?
A. Green
B. Yellow
C. Red
D. No change
✅ Answer: C. Red
2. Which of the following is a base?
A. Lemon juice
B. Vinegar
C. Soap solution
D. Tamarind water
✅ Answer: C. Soap solution
3. What is the colour of red litmus paper in a basic solution?
A. Red
B. Yellow
C. Blue
D. Green
✅ Answer: C. Blue
4. Which natural indicator is made from lichens?
A. Turmeric
B. Litmus
C. Rose extract
D. Onion
✅ Answer: B. Litmus
5. What colour does turmeric paper turn in a basic solution?
A. Yellow
B. Red-brown
C. Blue
D. Green
✅ Answer: B. Red-brown
6. What is the nature of vinegar?
A. Basic
B. Neutral
C. Acidic
D. Salty
✅ Answer: C. Acidic
7. Which sample is neutral in nature?
A. Lemon juice
B. Vinegar
C. Tap water
D. Soap solution
✅ Answer: C. Tap water
8. Which substance does not change the colour of litmus paper?
A. Salt solution
B. Vinegar
C. Soap solution
D. Baking soda
✅ Answer: A. Salt solution
9. What happens when an acid and a base mix in correct amounts?
A. Explosion
B. Turns black
C. Neutralisation
D. Melts
✅ Answer: C. Neutralisation
10. What are the products of neutralisation?
A. Acid + Fire
B. Salt + Water + Heat
C. Only water
D. Base + Cold
✅ Answer: B. Salt + Water + Heat
11. What should be applied on an ant bite?
A. Vinegar
B. Baking soda
C. Turmeric
D. Salt
✅ Answer: B. Baking soda
12. What is used to treat acidic soil?
A. Lemon juice
B. Vinegar
C. Lime (base)
D. Water
✅ Answer: C. Lime (base)
13. What does red rose extract turn in acidic solutions?
A. Green
B. Red
C. Yellow
D. Blue
✅ Answer: B. Red
14. Which indicator is good for detecting basic substances only?
A. Turmeric
B. Litmus
C. Onion
D. Red rose
✅ Answer: A. Turmeric
15. What is the taste of most acids?
A. Sweet
B. Bitter
C. Salty
D. Sour
✅ Answer: D. Sour
16. Which of these is a natural indicator?
A. Soap
B. Salt
C. Turmeric
D. Water
✅ Answer: C. Turmeric
17. What happens when you add lime water to lemon juice?
A. Turns blue
B. Turns red
C. Turns green
D. No change
✅ Answer: A. Turns blue
18. Why did the message appear on Ashwin’s greeting card?
A. He used magic ink
B. Turmeric and soap created a chemical change
C. It was printed
D. It glowed in the dark
✅ Answer: B. Turmeric and soap created a chemical change
19. Which flower helps detect acids and bases?
A. Rose
B. Lily
C. Sunflower
D. Jasmine
✅ Answer: A. Rose
20. What kind of reaction produces heat?
A. Melting
B. Neutralisation
C. Freezing
D. Boiling
✅ Answer: B. Neutralisation
21. What does baking soda feel like?
A. Sticky
B. Wet
C. Slippery
D. Rough
✅ Answer: C. Slippery
22. Which indicator changes its smell in acids and bases?
A. Litmus
B. Red rose
C. Onion
D. Vinegar
✅ Answer: C. Onion
23. What is the nature of washing powder solution?
A. Acidic
B. Basic
C. Neutral
D. Salty
✅ Answer: B. Basic
24. Which of these contains citric acid?
A. Milk
B. Soap
C. Lemon
D. Baking soda
✅ Answer: C. Lemon
25. What does the hydrangea flower colour depend on?
A. Age
B. Soil nature (acidic/basic)
C. Water
D. Temperature
✅ Answer: B. Soil nature (acidic/basic)
26. What turns turmeric paper red-brown?
A. Acid
B. Neutral substance
C. Base
D. Salt
✅ Answer: C. Base
27. Which one of these is not an acid-base indicator?
A. Turmeric
B. Red rose
C. Salt
D. Litmus
✅ Answer: C. Salt
28. What happens to blue litmus in basic solution?
A. Turns red
B. Turns green
C. No change
D. Turns purple
✅ Answer: C. No change
29. Which acid is present in tamarind?
A. Citric acid
B. Formic acid
C. Tartaric acid
D. Acetic acid
✅ Answer: C. Tartaric acid
30. Why did Aman see bubbles with vinegar on eggshells?
A. Vinegar boiled
B. Reaction with calcium carbonate
C. Soap was added
D. It dried
✅ Answer: B. Reaction with calcium carbonate
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