Why is it extremely dangerous to attempt to carry out a distillation in a completely closed apparatus

The main reason is to avoid explosion

Explanation:

When we carry out distillation process, it will get to a point where gases/steam are released due to evaporation, if we do not create a channel for exit they will build up in the apparatus and will ultimately lead to explosion

.) the observation by semmelweis that more mothers died of childbed fever when their doctors also worked in the morgue

the working equation for the angular size is the product of the physical size and 360 degrees divided by the product of two pi and distance from earth. the minimum size would be 0.559 degrees while the maximum size would be 0.49 degrees.