In general: [H+] = 10-pH
[H+] = 10-pH = 10-2
[H+] = 10-pH = 10-4
Because every 1 pH unit represents a change of ten-fold change in proton concentration, we can say that the concentration of the pH = 2 solution is 100 times more concentrated that that of the pH = 4 solution. Another way of saying this is that the pH = 2 solution has 100 times more protons that has the pH = 4 solution. Consequently, the pH = 2 solution is 100 times more acidic than the pH = 4 solution; or the pH = 4 solution is 100 times more basic than is the pH = 2 solution.
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