Question

. Classify the following reactions into a) Direct combination
c) Displacement d] Double decomposition
- The reactions are - i) Zinc hydro
heating gives zinc oxide & water ii] Zinc reacts with copper (II) sulphate to give zinc su
copper iii] Zinc sulphate reacts with ammonium hydroxide to give ammonium su
zinc hydroxide iv] Molten zinc at high temperatures, burns in air to give zinc oxide​

Answer 1

Answer:

Zinc hydroxide is a compound which decomposes to zinc oxide and water, hence it is a decomposition reaction.

Zn(OH)_2\ →\ ZnO+H_2OZn(OH)

2

→ ZnO+H

2

O

(ii) Zinc reacts with copper sulphate to give zinc sulphate and copper where zinc displaces copper because zinc is more reactive than copper.

(iii) Zinc sulphate reacts with ammonium hydroxide to give ammonium sulphate and zinc hydroxide where ions of sulphate and ammonia are exchanged, hence it is a double decomposition reaction.

ZnSO_4+2NH_4OH\ →\ Zn(OH)_2+(NH_4)_2SO_4ZnSO

4

+2NH

4

OH → Zn(OH)

2

+(NH

4

)

2

SO

4

(iv) Molten zinc burns in air to react with oxygen and forms zinc oxide which is a combination reaction