Classify the following reactions as synthesis (S), decomposition (D), single displacement (SD) or double displacement (DD). 1. CH4 + O2 → CO2 + H2O 2. Na + I2 → NaI 3. N2 + O2 → N2O 4. N2 + H2 → NH3 5. KI + Cl2 → KCl + I2 6. KClO3 → KCl + O2 7. S + O2 → SO3 8. H2O2 → H2O + O2 9. Na + H2O → NaOH + H2 10. C2H6 + O2 → CO2 + H2O