Chemistry - Eudiometry Question with Solution | TestHub

Let the volume of the gas be $V_x=50$ ml.

Let the volume of O₂ be $V_{O_2}=70$ ml.

Total volume of gases after reaction = $95$ ml.

Contraction after passing through KOH = $50$ ml.

KOH absorbs acidic gases like CO₂. So, volume of CO₂ formed = $50$ ml.

Remaining gases after CO₂ absorption = $95-50=45$ ml. This is unreacted O₂.

Volume of O₂ reacted = $70-45=25$ ml.

For CO, the reaction is:

$2\mathrm{CO}(g)+{\mathrm{O}}_2(g)\to 2{\mathrm{CO}}_2(g)$

Volume ratio: $2:1:2$

If $50$ ml of CO reacts, it consumes $25$ ml of O₂ and produces $50$ ml of CO₂.

This matches the calculated values.

The final answer is $\boxed{CO}$.