50 mL of a mixture of CO, CO2 and N2 was treated with KOH, reducing the volume to 40 mL. The remaining gas was mixed with 20 mL of O2 and exploded, and after cooling and KOH treatment the volume was 15 mL. The volume of CO in the original mixture was

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$50 mL$ of a mixture of $CO$ , $CO X_{2}$ and $N X_{2}$ was treated with KOH, reducing the volume to $40 mL$ . The remaining gas was mixed with $20 mL$ of $O X_{2}$ and exploded, and after cooling and KOH treatment the volume was $15 mL$ . The volume of $CO$ in the original mixture was

CO X_{2}

= 50 - 40 = 10 mL

. Let

CO = a

and

N X_{2} = 40 - a

2 CO + O X_{2} 2 CO X_{2}

consumes

a /2

O X_{2}

and the

CO X_{2}

formed is removed by KOH. Residual

= N X_{2} + leftover O X_{2} = (40 - a) + (20 - a /2) = 15

, so

1.5 a = 45

and

a = 30 mL