Answer
a. Left
b. Right
c. Left
d. No shift
e. No shift
f. Right
Work Step by Step
a. $H_2$ is added, thus the product side will increase and equilibrium will shift left to maintain equilibrium.
b. $I_2$ is removed, thus the product side will decrease and equilibrium will shift right to maintain equilibrium.
c. $HI$ is removed, thus the reactant side will decrease and equilibrium will shift left to maintain equilibrium.
d. If $Ar (g)$ is added, it will have no effect because argon gas in an inert gas, and inert gases have no effect on equilibrium, thus no shift occurs.
e. If the volume of the container is doubled, the concentrations of each compound or element will decrease, but it will not change the equilibrium because all of them are experiencing a decrease in concentration.
f. If the reaction is exothermic, you need to know the rule which states that "in an exothermic reaction, when temperature decreases, equilibrium moves right (and the value of K increases)." Thus the equilibrium moves right.