Question

Can any one please help me to answers this question i don't get it. thank in advance.

Answer 1

First, lets balance the reaction equation:
4Fe + 3O₂ → 2Fe₂O₃
It is visible form the equation that 4 moles of Fe require 3 moles of O₂
Molar ratio Fe/O₂ = 4/3 = 1.33
Molar ratio O₂/Fe = 3/4 = 0.75
Now, we check the molar ratios present:
Fe/O₂ = 6.8/8.9 = 0.76
O₂/Fe = 1.31

Thus, Iron is the limiting reactant because its ratio is not being fulfilled while the ratio of O₂ is surpassed.