يا جماعة هل أواني البرستو موجوده في كتاب المدرسة

I take it in English , The answer should be :

* To achieve saturated vapour pressure inwhich the amount of liquid molecules which change to gas equal the amount of gas which change to liquid .
* To make cooking faster
* To achieve a temperature higher than 100 c without the escaping of water from the cooking medium