NEET Solved Paper 2017 Question 24
Question: A 20 litre container at 400 K contains $ CO _2(g) $ pressure 0.4 atm and an excess of SrO (neglect the volume of solid SrO). The volume of the containers is now decreased by moving the movable piston fitted in the container. The maximum volume of the container, when pressure of $ CO _2 $ attains its maximum value, will be (Given that: $ SrCO _3(s)=SrO(s)+CO _2(g). $ $ K _{p}=1.6,atm) $
Options:
A) 2 litre
B) 5 litre
C) 10 litre
D) 4 litre
Show Answer
Answer:
Correct Answer: B
Solution:

Max. pressure of $ CO _2= $ Pressure of $ CO _2 $ at equilibrium
For reaction, $ SrCO _3(s)SrO(s)+CO _2 $
$ K _{p}={P _{CO _2}}=1.6,\text{atm =} $ maximum pressure of $ CO _2 $
Volume of container at this stage, $ V=\frac{nRT}{P} $ (i) Since container is sealed and reaction was not earlier at equilibrium
$ \therefore $ $ n=constant $ $ n=\frac{PV}{RT}=\frac{0.4\times 20}{RT} $ ?(ii) Put equation (ii) in equation (i) $ V=[ \frac{0.4\times 20}{RT} ]\frac{RT}{1.6}=5L $