Question

Zinc oxide was added to dilute HCl and zinc oxide was added to dilute NaOH. 

 Write down the changes that will be seen in each instance and explain the reason behind it.

(f)  Zinc oxide was added to dilute HCl and zinc oxide was added to dilute NaOH.

Answer 1

When Zinc oxide is added to dilute HCl, it forms zinc chloride and water and neutralization reaction takes place. In this reaction zinc oxide is basic oxide
ZnO +2HCl → ZnCl₂ + H₂O

When zinc oxide was added to dilute NaOH. Zinc oxide reacts with sodium hydroxide and it forms zincate sodium and water. In this reaction zinc oxide is acidic oxide

ZnO + 2NaOH→Na₂ZnO₂ + H₂O

Therefore zinc oxide is an amphoteric oxide because it shows both acidic and basic properties.