Question

Iron can be obtained by reduction of iron oxide $\left(F{e}_3{O}_4\right)$ with CO according to the reaction:
$F{e}_3{O}_4+4CO\to 3Fe+4C{O}_2$
How many kg of $F{e}_3{O}_4$ should be heated with CO to get 3 kg of iron?

• A. $8.12kg$
• B. $4.14kg$
• C. $6.94kg$
• D. $16.8kg$

Answer 1

The correct option is B $4.14kg$

Chemical reaction involved is:

$F{e}_3{O}_4+4CO\to 3Fe+4C{O}_2$

Molar mass of $Fe=56g$

Molar mass of $F{e}_3{O}_4=3\times 56+4\times 16=232g$

According to the balanced reaction 3 mol ($3\times 56=168g$) of $Fe$ is obtained by 1 mol ($232g$) of $F{e}_3{O}_4$

$\therefore 3kg=3000gFe$ will obtained from $\frac{232}{168}\times 3000=4142.8gF{e}_3{O}_4$ or $4.142kgF{e}_3{O}_4$

Hence, option B is correct.