Answer:
1 mole
Step-by-step explanation:
First thing's first we have to write out the chemical equation for the reaction.
Hydrogen + Iodine --> Hydrogen Iodide
H2(g) + I2(s) → 2HI(g)
Upon observing the stoichiometry of the reaction, we can tell that;
1 mole of H2 reacts with 1 mol of I2