C8H18 (l) + 8 O2 (g) → 9 H2 (g) + 8 CO2 (g)
This is an oxidation-reduction (redox) reaction:
8 C-9/4 - 50 e- → 8 CIV (oxidation)
18 HI + 18 e- → 18 H0 (reduction)
16 O0 + 32 e- → 16 O-II (reduction)
C8H18 is a reducing agent, C8H18 is an oxidizing agent, O2 is an oxidizing agent.