Question

The number of atoms of $Cr$ and $O$ in a compound is $4.8\times {10}^{10}$ and $9.6\times {10}^{10}$ respectively. Its empirical formula is :

• A. $C{r}_2{O}_3$
• B. $Cr{O}_2$
• C. $C{r}_2{O}_4$
• D. $Cr{O}_5$

Answer 1

Answer: (B)

$Cr{O}_2$

The number of atoms of $Cr$ and $O$ in a compound is $4.8\times {10}^{10}$ and $9.6\times {10}^{10}$ respectively.

The ratio of the number of atoms of Cr to O is $\frac{4.8\times {10}^{10}}{9.6\times {10}^{10}}=\frac{1}{2}$.

Its empirical formula is $Cr{O}_2$.