At room temperature following traction goes to completion
`2AB(g)+B_(2)(g)rarr2AB_(2)(s)`
`AB_(2)` is solid with negligble vapour pressure below `0^(@)C`. At 300 K, the AB in the smaller flask exerts a pressure of 3 atm and in the larger flask `B_(2)` exerts a pressure of 1 atm at 400 K when they are separated out by a close valve, The gases are mixed by opening the stop cock and after the end of the reaction the flask are cooled to 250 K

The final pressure is :

Options

A. 0.156 atm
B. 0.3125 atm
C. 0.625 atm
D. 3.2 atm

Answer

c

Explanation

(c) `n_(AB)=(3xx8.21)/(0.0821xx300)=1,`
`n_(B_(2))=(1xx8.21)/(0.0821xx400)=0.25`
`2AB(g)+B_(2)(g)rarr2AB_(2)(s)`
`{:("Initial moles",1,0.25),("After reaction",0.5,0):}`
`P_(AB)xx(8.21+8.21)=0.5xx0.0821xx250`
`P_(AB)=0.625atm`