Question

The correct formula of aluminium oxide is:

• A. $\mathrm{AlO}$
• B. ${\mathrm{AlO}}_2$
• C. ${\mathrm{AlO}}_3$
• D. ${\mathrm{Al}}_2{\mathrm{O}}_3$

Answer 1

The correct option is D

${\mathrm{Al}}_2{\mathrm{O}}_3$

Explanation for correct option:

Option D

Chemical formula:

• The formula of a substance is the symbolic representation of a chemical substance.
• To write the formula of a chemical substance, the valency and the symbol of the various atoms or radicals present in it must be known.
• For example, the chemical formula of sulphuric acid is ${\mathrm{H}}_2{\mathrm{SO}}_4$.
• Aluminum oxide is formed by the combination of aluminum ion( ${\mathrm{Al}}^{3+}$) and oxygen ion ( ${\mathrm{O}}^{2-}$).
• The valency of aluminum is three and the valency of oxygen is two, on applying the criss-cross method we get the formula of aluminum oxide.

Hence, the correct formula of aluminum oxide is ${\mathrm{Al}}_2{\mathrm{O}}_3$.

Therefore, option D is correct.