Solutions Question 396
Question: At $ 20{}^\circ C $ and 1.00 atm partial pressure of hydrogen, 18 mL of hydrogen, measured at STP, dissolves in 1L of water. If water at $ 20{}^\circ C $ is exposed to a gaseous mixture having a total pressure of 1400 Torr (excluding the vapour pressure of water) and containing 68.5% $ H_2 $ by volume, find the volume of $ H_2, $ measured at STP, which will dissolve in 1L of water.
Options:
A) 18 mL
B) 12 mL
C) 23 mL
D) 121 mL
Show Answer
Answer:
Correct Answer: C
Solution:
$ p(H_2)=(1400Torr)(0.685) $
$ =959Torr\equiv 959/760atm=1.26atm $
According to Henry’s law
Amount of gas absorbed is directly proportional to pressure.
Hence $ \frac{V}{18mL}=\frac{1.26atm}{1atm} $
$ V=23mL $
