1. Carbon monoxide can be prepared by the reaction of carbon with limited amount of oxygen.
2C + O2 → 2CO
2. On industrial scale carbon monoxide is produced by the reaction of carbon with air.
3. Pure carbon monoxide is prepared by warming methanoic acid with concentrated sulphuric acid which act as a dehydrating agent.
HCOOH + H2SO4 → CO + H2O + H2SO4