Question

Which of the following is not a basic flux?

• A. ${\text{CaCO}}_3$
• B. ${\text{Ca(OH)}}_2$
• C. ${\text{SiO}}_2$
• D. $\text{CaO}$

Answer 1

The correct option is C ${\text{SiO}}_2$

Flux is a substance that is added to the ore to remove impurities (gangue) from it. It reacts with gangue to form slag.
If the gangue is a acidic substance, basic substance is used as flux and vice versa.
In the above options only ${\text{SiO}}_2$ is an acidic flux whereas, remaining are basic flux.