A
Carbon monoxide gas can be prepared in lab by heating formic acid or oxalic acid with conc. H2SO4.
Procedure: Small amount of oxalic acid crystal is taken in a round- bottomed flask and all the apparatus are fitted as shown in figure. When conc. H2SO4 is poured in the flask through thistle funnel and heated then a mixture of CO and CO2 gas is formed. The mixture of gas is passed through a bottle containing NaOH solution where the CO2 gas is absorbed by NaOH.
2NaOH + CO2 → Na2CO3 + H2O
The pure CO gas is then collected in a gas jar by downward displacement of water.