Consider two solutions: solution X has a pH of 4; solution Y has a pH of 7. From this information, we can reasonably conclude that the concentration of hydrogen ions (H⁺) or hydronium ions (H₃O⁺) in solution X is thousand times as great as the concentration of hydrogen ions or hydronium ions in solution Y.
Solution X: c(H⁺) = 10∧-pH = 10⁻⁴ mol/L = 0,0001 mol/L.
Solution Y: c(H⁺) = 10⁻⁷ mol/L = 0,0000001 mol/L.
0,0001 mol/L / 0,0000001 mol/L = 1000.