Question

it is not safe to burn a call in a closed room give reason

Answer 1

It is not safe to burn coal in a closed room because coal, being a fossil fuel, releases carbon dioxide, carbon monoxide and some oxides of sulphur, etc on combustion, which are toxic to human beings if they are exposed to them for a long period of time. In a closed room, there is no ventilation. So, the person sleeping in that room may die in his sleep of suffocation and CO poisoning, as the carbon monoxide gas mixes with the haemoglobin in blood thereby forming carboxyhemoglobin, which greatly reduces the ability of red blood cells to carry oxygen to other body cells.