question_answer

A sample of air contains only \[{{N}_{2}},{{O}_{2}}\] and \[{{H}_{2}}O.\] It is saturated with water vapour and the total pressure is 640 torr. the vapour pressure of water is 40 torr and the molar ratio of \[{{N}_{2}}:{{O}_{2}}\] is \[3:1\]. The partial pressure of \[{{N}_{2}}\] in the sample is :-

A)  480 torr           

B)  600 torr

C)  525 torr           

D)  450 torr