In severe cold weather, a family burnt wood in the room during the night by keeping the windows close. After sometime, they felt suffocated. They immediately opened the windows and got relief. What did actually happen ?

Explanation

When wood burns, the carbon present is oxidised to carbon dioxide `(CO_(2))` which is non-poisonous. When the windows are close, the air or oxygen cannot enter the room. In the incomplete supply of oxygen, carbon is oxidised to carbon monoxide (CO) which is a highly poisonous gas. It caused suffocation in a close room. On opening the windows, the poisonous gas slowly diffused out the room and fresh air came inside. That is how the poisonous effect of carbon monoxide gas was neutralised and the family got relief.