Question

How many number of aluminium ions are present in 0.051 g of aluminium oxide?

• A. $6.023\times {10}^{20}$ ions
• B. $3$ ions
• C. $6.023\times {10}^{23}$ ions
• D. $9$ ions

Answer 1

The correct option is A $6.023\times {10}^{20}$ ions

Molar mass of aluminium oxide, $A{l}_2{O}_3=2\times 27+3\times 16=102$ g

$A{l}_2{O}_3⟶2A{l}^{3+}+3O^{2-}$

Number of aluminium ions in $A{l}_2{O}_3$ = 2

Number of ions in 0.051 g of aluminium oxide $=\frac{2\times 6.022\times {10}^{23}}{102}\times 0.051$

$=6.023\times {10}^{20}$ of Al ions

Hence, option $A$ is correct.