Question

is not a basic flux.

• A. $CaC{O}_3$
• B. $Si{O}_2$
• C. $MgO$
• D. $Ca(OH{)}_2$

Answer 1

The correct option is B $Si{O}_2$

Flux is a substance that is added during smelting to convert infusible impurities or gangue into fusible material known as slag.
$Si{O}_2$ is a non-metallic or an acidic oxide. It can be used as an acidic flux to remove basic impurities such as CaO.
In the extraction of Fe, $Si{O}_2$ is a gangue that is treated with basic flux (CaO) to form the fusible slag - calcium silicate.

$CaO$ + $Si{O}_2$ $\to$ $CaSi{O}_3$

(Flux) (Impurities) (Slag)