Question

Silicon carbide, an abrasive, is made by the reaction of silicon dioxide with graphite. SiO2 +3C SiC + 2CO If 2 moles of SiO2 react with 5 moles of C, what is the limiting reactant?

Answer 1

Answer : The limiting reactant is, carbon (C)

Explanation : Given,

Moles of $SiO_2$ = 2 moles

Moles of C = 5 moles

Now we have to calculate the limiting and excess reagent.

The given balanced chemical reaction is:

$SiO_2+3C\rightarrow SiC+2CO$

From the balanced reaction we conclude that

As, 3 mole of $C$ react with 1 mole of $SiO_2$

So, 5 moles of $C$ react with $\frac{5}{3}=1.67$ moles of $SiO_2$

From this we conclude that, $SiO_2$ is an excess reagent because the given moles are greater than the required moles and $C$ is a limiting reagent and it limits the formation of product.

Thus, the limiting reactant is, carbon (C)