Question

The number of atoms of Cr and O are $4.8\times {10}^{10}$ 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. None of these

Answer 1

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

Number of atoms of Cr = $4.8\times {10}^{10}$

Number of atoms of O = $9.6\times {10}^{10}$

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

Hence, empirical formula of the compound is $Cr{O}_2$