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Chemical reactivity
6 Class 9 Chemistry questions with answers and explanations.
Printable worksheet with answer key
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Which metal is the most reactive?
- 1 Copper
- 2 Potassium
- 3 Zinc
- 4 Iron
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Correct answer: Potassium
Potassium is at the top of the reactivity series of these four.
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Which metal reacts with cold water to give hydrogen?
- 1 Sodium
- 2 Gold
- 3 Silver
- 4 Copper
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Correct answer: Sodium
Sodium reacts vigorously with cold water. Copper, silver and gold do not react with water.
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When zinc is added to copper sulphate solution, a displacement reaction occurs because zinc is:
- 1 A noble gas
- 2 Less reactive than copper
- 3 A non-metal
- 4 More reactive than copper
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Correct answer: More reactive than copper
A more reactive metal displaces a less reactive one from its salt solution.
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Which of these is the least reactive?
- 1 Sodium
- 2 Calcium
- 3 Gold
- 4 Magnesium
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Correct answer: Gold
Gold is very unreactive and is found free in nature.
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Alkali metals are stored under kerosene oil to:
- 1 Make them heavy
- 2 Prevent reaction with air and moisture
- 3 Keep them cool only
- 4 Make them shiny
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Correct answer: Prevent reaction with air and moisture
They react quickly with oxygen and water vapour in air.
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Reactivity of halogens down group VIIA:
- 1 Increases
- 2 Stays the same
- 3 First increases then decreases
- 4 Decreases
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Correct answer: Decreases
Fluorine is the most reactive halogen and reactivity falls down the group.