PLEASE HELP, If I have hydrochloric acid and Iron and mix them how do I know if it'll be FeCl2 or FeCl3?

I have all the info and I know how to calculate yield ect, what I dont understand is how to predict how many Cl with stick with the Fe, my guess would be if there is a ratio of at least 3 Cl per Fe molecule than Id get Cl 3 and if theres less it would be Cl2 but somethings tells me I may be wrong? Please explain, you can use any examples