If the acetylene tank contains 37.0 mil of C2H2 and the oxygen tank contains 81.0 mol of O2, what is the limiting reactant for this reaction
2C2H2(l)+502(g) 4CO2(g)+2H2O(g)

Explanation:

2C₂H₂(l)  +  50₂(g) =   4CO₂(g)  +  2H₂O(g)

2 mol          5 mol

2 mol of C₂H₂ reacts with 5 mol of O₂

37 mol of C₂H₂  will require 5/2 x 37 mol of O₂

= 92.5 mol of O₂

But oxygen available is only 81 mol so formation of product will be controlled by oxygen available . Hence oxygen is the limiting factor.