Question

Consider the combustion reaction for acetylene.


2C2H2(l) + 5O2(g) Right arrow. 4CO2(g) + 2H2O(g)


If the acetylene tank contains 37.0 mol of C2H2 and the oxygen tank contains 81.0 mol of O2, what is the limiting reactant for this reaction?
C2H2
O2
CO2
H2O

Answer 1

O2 is the limiting reactant.

Reason: 2 C2H2 require 5 O2, so 1 C2H2 requires 2.5 O2. For 37.0 mol C2H2 you'd need 37.0×2.5 = 92.5 mol O2, but only 81.0 mol O2 are available. Therefore oxygen runs out first.