Question

The ore of a metal contains P₂O₅ as impurity. The suitable flux for the ore is ______.

Options

• SiO₂

• CaO

• B₂O₃

• PbO

Answer 1

CaO

Explanation:

When the ore contains P₂O₅ as an impurity, it is an acidic impurity. For acidic impurities like P₂O₅, a basic flux such as CaO (lime) is used. The flux reacts with the acidic impurity to form a fusible slag which can be removed easily. Thus, CaO is the suitable flux for an ore containing P₂O₅ impurity because it combines with P₂O₅ and forms slag, facilitating the removal of impurity during smelting.