posted by Ben on .
How can i determine that the volume is decreasing?
Of the following equilibria, only ??? will shift to the left in response to a decrease in volume.
A) 2HI <->(g) H2 (g) + I2 (g)
B) N2 (g) + 3 H2 (g)<-> 2 NH3 (g)
C) 4 Fe (s) + 3 O2 (g)<-> 2 Fe2O3 (s)
D) 2 SO3(g)<-> 2 SO2 (g) + O2 (g)
E) H2 (g) + Cl2 (g) <-> 2 HCl (g)
The easy way to do is to say, "volume gos down, pressure goes ??. Of course the answer is up. All of these are gaseous reactions, so an increase in P will cause the equilibrium to shift to the side with the smaller number of moles of gas. So you look at each one.
A no change in number of moles so unaffected.
B. P goes up, rxn shift to the right.
C. P goes up, rxn shifts to the right.
D. P goes up, rxn shifts to the left.
E. P goes up, no change.