Question

49. The variation of vapour pressure of different liquids with temperature is shown in Fig.
I Calculate graphically boiling points of liquids A and B.
ii. If we take liquid C in a closed vessel and heat it continuously. At what temperature will it
boil?
ül. At high altitudes, atmospheric pressure is low (say 60 mm Hg). At what temperature liquid
D boils?
iv. A pressure cooker is used for cooking food at the hill station. Explain in terms of vapour
pressure why is it so?​

Answer 1

Explanation:

(i) Boiling point of A = 315K approximately.

Boiling point of B = 345K approximately.

(ii) In a closed vessel, liquid C will not boil because pressure is kept on increasing.

(iii) Temperature corresponding to 60mm Hg = 313K.

(iv) A liquid boils when vapour pressure of liquid becomes equal to atmospheric pressure. 

On hills water boils at low temperature, because atmospheric pressure is low is high. altitude.

But when pressure cooker is used, the vapour pressure of water is increased due to which water boils at even low temperature within a short period of time.