Question

Write a balanced equation to convert iron to triferric tetroxide.
A.) $3Fe + 2{O_2} \to F{e_2}{O_3}$
B.) $2Fe + {O_2} \to 2FeO$
C.) $3Fe + 4{O_2} \to F{e_3}{O_4}$
D.) $3Fe + 2{O_2} \to F{e_3}{O_4}$

Answer 1

The given chemical reaction can be balanced if we know the formula of the product and it will be balanced if the number of atoms of an element in the reactants is the same to that of the number of atoms of that element in the product.

Complete step by step answer:
In the given question, to convert iron into tri-ferric oxide first we need to know the chemical formula of triferric tetroxide. The triferric tetroxide has the chemical formula as $F{e_3}{O_4}$ in which there are three iron atoms and four oxygen atoms. Therefore, in the product side of the reaction there should be $F{e_3}{O_4}$. Also, we know that tri-ferric oxide is formed when the reaction between iron($Fe$) and oxygen (${O_2}$) occurs. Therefore, in the reactants of the reaction there should be iron and oxygen. Also, to get the balanced chemical equation the number of atoms of iron at the left side of the reaction should be equal to the number of iron atoms at the right side of the reaction and similarly the number of oxygen atoms at the left side of the reaction should be equal to the number of oxygen atoms at the right side of the reaction.
In option A.) and B.) as we can see that the product obtained is not triferric tetroxide that is $F{e_3}{O_4}$. Therefore, these are not the right chemical equation for production of tri-ferric oxide.
In option C.)
$3Fe + 4{O_2} \to F{e_3}{O_4}$
In the given reaction, the number of iron($Fe$) atoms at the left side is the same as in the right side that is three. But the number of oxygen atoms at the left side is eight and at the right side it is four. So, this is not the balanced chemical equation.
In option D.)
$3Fe + 2{O_2} \to F{e_3}{O_4}$
In the given reaction, the number of iron atoms is three on both sides of the chemical reaction and also the number of oxygen atoms is equal in both die of the reaction that is four.
Hence, option C.) is the correct answer.

Note:
Remember that when iron($Fe$) is reacted with oxygen gas(${O_2}$) then it gives triferric tetroxide($F{e_2}{O_3}$) and when iron($Fe$) reacts with water(${H_2}O$) then it gives same triferric tetroxide($F{e_2}{O_3}$) but along with it, hydrogen gas(${H_2}$) is produced in the product. This can be given as:
$2Fe + 3{H_2}O \to F{e_2}{O_3} + 3{H_2}$