The chemical formula for pH is

**pH = - log _{10}[H^{+}]** where [H

Example:Calculate the pH of a 0.25 M or 0.25 mol L^{-1}solution.pH = - log

_{10}[H^{+}]pH = - log

_{10}[0.25]pH = -(-0.60) since log

_{10}[0.25] = -0.60pH = 0.60

Calculate the pH of the following solutions of hydrogen ions. Use the pH calculator provided

pH = -0.70 5.0 M |
pH = 0.65 0.225 M |
pH = -0.30 2.0 M |
pH = 0.0 1.0 M |
pH = 0.52 0.30 M |

pH = 0.30 0.50 M |
pH = 1.65 0.0225 M |
pH = 0.70 0.20 M |
pH = 1.0 0.01 M |
pH = 2.52 0.0030 M |

For strong monoprotic acids like hydrochloric acid HCl and nitric acid HNO_{3} the concentration of the acid is equal to the concentration of H^{+} ions.

Example:Calculate the pH of a 0.10 M or 0.10 mol L^{-1}solution of nitric acid.HNO

_{3}(aq) →H^{+}(aq) + NO_{3}^{-}(aq)

0.10M 0.10M 0.10M∴ [H

^{+}] = 0.10 M

pH = - log

_{10}[H^{+}]pH = - log

_{10}[0.10]pH = -(-1.0) since log

_{10}[0.10] = -1.0pH = 1.0

However, for diprotic acids like sulfuric acid H_{2}SO_{4} this is not the case. A diprotic acid produces two moles of hydrogen ions per mole of acid.

Example:Calculate the pH of a 010 M or 0.10 mol L^{-1}solution of sulfuric acid.Sulfuric acid is a diprotic acid. When it fully dissociates it produces twice the number of moles of H

^{+}ions.H

_{2}SO_{4}(aq) →2H^{+}(aq) + SO_{4}^{2-}(aq)

0.10M 0.20M 0.10M∴ [H

^{+}] = 0.20 M which is twice the concentration of H_{2}SO_{4}

pH = - log

_{10}[H^{+}]pH = - log

_{10}[0.20]pH = -(-0.70) since log

_{10}[0.20] = -0.70pH = 0.70

Calculate the pH of the following solutions of strongs acids. Use the pH calculator provided

pH = -1.0 5.0 M H _{2}SO_{4} |
pH = 0.19 0.55 M HNO _{3} |
pH = -0.46 0.350 M HCl |
pH = -0.30 2.0 M HCl |
pH = 0.40 0.20 M H _{2}SO_{4} |

pH = 0.22 0.60 M HNO _{3} |
pH = 1.40 0.0325 M HCl |
pH = -0.04 0.550 M H _{2}SO_{4} |
pH = 0.0 1.0 M HNO _{3} |
pH = 2.10 0.0040 M H _{2}SO_{4} |