Question
Why is Na2O called a basic oxide but ZnO is called an amphoteric oxide ? Give equations.
Answer
Na2O is called a basic oxide because it reacts with water to form a strong base, sodium hydroxide (NaOH), which increases the pH of the solution. The balanced chemical equation for the reaction between Na2O and water is:
Na2O + H2O → 2NaOH
On the other hand, ZnO is called an amphoteric oxide because it can react as both an acid and a base. It can react with both acids and bases to form salts, and it can also react with water to form both an acidic and basic solution. The balanced chemical equations for the reactions of ZnO with an acid and a base are:
ZnO + 2HCl → ZnCl2 + H2O
ZnO + 2NaOH → Na2ZnO2 + H2O