Chemical reactivity

Written by Dr. Ayesha Nadeem (Chemistry)

Class 9 · Chemistry · 10 questions

Name: ____________________ Date: ____________

Which metal is the most reactive?
- A Copper
- B Potassium
- C Zinc
- D Iron
Which metal reacts with cold water to give hydrogen?
- A Sodium
- B Gold
- C Silver
- D Copper
When zinc is added to copper sulphate solution, a displacement reaction occurs because zinc is:
- A A noble gas
- B Less reactive than copper
- C A non-metal
- D More reactive than copper
Which of these is the least reactive?
- A Sodium
- B Calcium
- C Gold
- D Magnesium
Alkali metals are stored under kerosene oil to:
- A Make them heavy
- B Prevent reaction with air and moisture
- C Keep them cool only
- D Make them shiny
Reactivity of halogens down group VIIA:
- A Increases
- B Stays the same
- C First increases then decreases
- D Decreases
Which of these metals does not react with dilute hydrochloric acid?
- A Zinc
- B Copper
- C Magnesium
- D Iron
Rusting of iron needs:
- A Oxygen and water
- B Only water
- C Only oxygen
- D Nitrogen
The metal extracted by electrolysis because it is very reactive is:
- A Sodium
- B Iron
- C Copper
- D Gold
A reaction in which a more reactive element replaces a less reactive one is a:
- A Decomposition
- B Neutralisation
- C Displacement reaction
- D Combination reaction

Answer key

1. B, 2. A, 3. D, 4. C, 5. B, 6. D, 7. B, 8. A, 9. A, 10. C

Potassium is at the top of the reactivity series of these four.
Sodium reacts vigorously with cold water. Copper, silver and gold do not react with water.
A more reactive metal displaces a less reactive one from its salt solution.
Gold is very unreactive and is found free in nature.
They react quickly with oxygen and water vapour in air.
Fluorine is the most reactive halogen and reactivity falls down the group.
Copper is below hydrogen in the reactivity series.
Both oxygen and water are required.
Very reactive metals are extracted by electrolysis of their molten compounds.
This is a displacement reaction.