I need someone who wont guess and help me figure out which one has a greater activation energy?

Question

1. A 1cm. cube of Fe reacting with 50ml. of 1M HCL producing hydrogen at a rate of 1ml. per sec.
or A 1cm. cube of Mg reacting with 50ml. of 1 M HCL producing hydrogen at a rate of 5 ml. per sec.

Answer 1

If you believe that the rate of a reaction can be equated to the number of productive collisions per second, and that a high activation energy reduces the number of productive collisions per second, and that the total number of collisions per second in these two cases must be the same, the iron reaction must have the higher activation energy.

Answer 2

Using periodic properties, you will see that Magnesium is a much more reactive substance than Fe. They're both combined with an acid, so a displacement reaction will occur.

Also Magnesium oxidates easier than Fe, so it will react better. I'm not sure activation energy was the right term here. More like a RedOx problem