Chemistry - Chemical Equilibrium Question with Solution | TestHub
A gaseous substance XY2(g) converts to XY(g) in the presence of solid X as: XY2(g) + X(s) ⇌ 2XY(g). The initial pressure and the equilibrium pressure are 0.6 and 0.9 bar, respectively. Now the equilibrium mixture is expanded reversibly and isothermally till the gas pressure falls to 0.5 bar. Which of the following statements is/are correct?
Options:(select one or more)
Answer:
Solution:
Let x bar of XY2 react: PXY2 = 0.6 - x and PXY = 2x 0.6 + x = 0.9, so x = 0.3 bar
PXY2 = 0.3 bar and PXY = 0.6 bar
KP = (0.6)2/0.3 = 1.2 bar, so (c) is wrong
After expansion let PXY = b and PXY2 = 0.5 - b
b2 = 1.2(0.5 - b), giving b2 + 1.2b - 0.6 = 0
b = [-1.2 + √(1.44 + 2.4)]/2 = 0.380 bar and PXY2 = 0.120 bar
Volume per cent of XY = 0.380/0.5 = 76%, so (a) is correct
Volume per cent of XY2 = 24%, so (b) is wrong
Pressure ratio = 0.9/0.5 = 1.8, so (d) is correct
The correct statements are (a) and (d).
