When iron metal reacts with sulfuric acid, it produces iron (iii) sulfate and hydrogen gas. balance the equation: fe + h2so4 → fe2(so4)3 + h2. explain why it is necessary to balance chemical equations and why coefficients can be added to an equation, but subscripts cannot be changed.

2fe + 3h2so4 -> fe2(so4)3 + 3h2

it is necessary to balance equations in order to get the proper amount of reactants as well as products in order not to make a miscalculation.

you cannot change the subscripts as that would change the substance itself. for instance, diatomic elements such as h2 only have the subscript two when a gas. another example would be so4, if you were to change the subscript, the element would no longer be sulfate.

we change the coefficients instead as that only changes the number of molecules rather than the substance itself.

hope this !

answer:

technetium is the most reactive. this is followed by silver. the least reactive out of these three elements is strontium.