Carbon monoxide
Laboratory preparation

Carbon monoxide is conveniently produced in the laboratory by the dehydration of formic acid or oxalic acid, for example with concentrated sulfuric acid. Another method is heating an intimate mixture of powdered zinc metal and calcium carbonate, which releases CO and leaves behind zinc oxide and calcium oxide:

Silver nitrate and iodoform also afford carbon monoxide:

Finally, metal oxalate salts release CO upon heating, leaving a carbonate as byproduct:
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