Question

Which of the following oxides is acidic in nature?

• A. ${\mathrm{SiO}}_2$
• B. ${\mathrm{Ga}}_2{\mathrm{O}}_3$
• C. ${\mathrm{Al}}_2{\mathrm{O}}_3$
• D. ${\mathrm{As}}_2{\mathrm{O}}_3$

Answer 1

The correct option is A

${\mathrm{SiO}}_2$

Explanation of the correct option:

(A) ${\mathrm{SiO}}_2$

• ${\mathrm{SiO}}_2$ is acidic in nature and it reacts with strong bases.
• ${\mathrm{SiO}}_2$ react with a hot, concentrated $\mathrm{NaOH}$ solution and results in a colorless solution of sodium silicate$\left({\mathrm{Na}}_2{\mathrm{SiO}}_3\right)$.

${\mathrm{SiO}}_2\left(\mathrm{g}\right)+2\mathrm{NaOH}\left(\mathrm{aq}\right)\to {\mathrm{Na}}_2{\mathrm{SiO}}_3\left(\mathrm{aq}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)$

Explanation of incorrect options:

(B) ${\mathrm{Ga}}_2{\mathrm{O}}_3$

• ${\mathrm{Ga}}_2{\mathrm{O}}_3$ is an amphoteric oxide; it can react with both acid and base.

(C) ${\mathrm{Al}}_2{\mathrm{O}}_3$

• ${\mathrm{Al}}_2{\mathrm{O}}_3$ is also an amphoteric oxide, they can react with both base and acid.

(D) ${\mathrm{As}}_2{\mathrm{O}}_3$

• ${\mathrm{As}}_2{\mathrm{O}}_3$ is amphoteric in nature and it dissolves in dilute hydrochloride and also in warm alkalis.

Hence, option (A) is the correct option., ${\mathrm{SiO}}_2$ is acidic in nature.