Answer: 3. No displacement, zinc is most reactive.
4. Calcium Chloride, Calcium is most reactive.
5. No displacement, Copper is most reactive
6. No displacement, Calcium is most reactive
7. Hydrogen Oxide, Hydrogen is most reactive
8. Carbon oxide, Carbon is most reactive
9. No displacement, Aluminum is most reactive
10. Potassium Kryptide + Lead, no displacement, Potassium is most reactive.