Adding a base to a solution would...?

Raise the pH

decrease [H+]

Explanation:

=> Adding base would raise the pH (Bases have more pH and Acids have less pH)

=> Adding base would decrease the concentration of [H+] ions as it contains hydroxyl ions which neutralized with H+ ions so as a result the concentration of [H+] ions decreases.

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 !