In which direction will the position of the equilibrium 2HI(g) ⇌ H2(g) + I2(g) be shifted for each of the following changes?
a. H2(g) is added.
b. I2(g) is removed.
c. HI(g) is removed.
d. In a rigid reaction container, some Ar(g) is added.
e. The volume of the container is doubled.
f. The temperature is decreased (the reaction is exothermic).