what is the different between round bottom flask and flat bottom flask

Round bottom flasks are a type of flasks with spherical bottoms that is used in laboratories for chemical work. Round bottom flasks are usually held by a clamp when being used and rest on a cork ring for the flask to stand on its own.

The round bottoms on these types of flasks allow more uniform heating and/or boiling of liquid. Thus, round-bottom flasks are used in a variety of applications where the contents are heated or boiled. Round-bottom flasks are used in distillation by chemists as distilling flasks and receiving flasks. This flask shape is also more resistant to fracturing under vacuum, as a sphere more evenly distributes stress across its surface.

A flat bottom flask is a glass flask that is used in the laboratory for holding chemicals (reagent flasks) whose bottom is flat and can thus be conveniently placed on the table or in a cabinet. These flasks cannot withstand too much pressure or temperature differences, due to the stresses which arise in a flat bottom, these flasks are usually made of weaker glass than reaction flasks. This flask can be used to make chemical reactions in liquid phase, to make titration, mixing solutions and also for boiling since it can stand alone.