Question

what is the purpose of round bottom flask in fractional distillation​

Answer 1

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.

Answer 2

Answer:

$\huge \colorbox{pink}{ANSWER}$

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.