Question

A certain oxide of iron contains 2.5 g of oxygen for every 7.0 g of iron. If it is regarded as mixture of FeO and $F{e}_2{O}_3$ in the weight ratio x : y, what is x : y, (atomic weight of iron = 56)

• A. 9 : 10
• B. 9 : 20
• C. 14 : 5
• D. 1:1

Answer 1

The correct option is A

9 : 10

If x gm FeO and y gm$F{e}_2{O}_3$ is taken

$m_{F}e$=$\frac{x}{72}$+$\frac{2xy}{160}$56

$m_o$ =$\frac{x}{72}$+$\frac{3xy}{160}$16

$\frac{m_{F}e}{m_o}$ =$\frac{7}{2.5}$

$\frac{\frac{x}{72}+\frac{y}{80}56}{\frac{x}{72}+\frac{8y}{160}}$` =$\frac{7\times 2}{5}$

$\frac{x}{y}$ =$\frac{9}{10}$