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Strong acids versus weak acids

  • How do you describe a strong acid from a weak acid chemically?
  • Strong acids are acids that are completely or nearly 100% ionized in their solutions.
  • It means nearly or all the molecules you put in the solution are completely broken into ions.
  • (An ion is simply a name given to an atom that has lost or gained an electron. If the ion has more electrons than protons, it becomes a negative ion called anion. If the ion has less electrons than protons, it becomes a positive ion called cation. )

Examples of strong acids

Notice the H+ ions released

  • HCl - hydrochloric acid -->H+ + Cl-
  • HNO3 - nitric acid --> H+ + NO3-
  • H2SO4 - sulfuric acid --> 2H+ + SO42-
  • HBr - hydrobromic acid --> H+ + Br-

weak acids completely ionize in solutions


Examples of weak acids

  • HO2C2O2H - oxalic acid
  • H2SO3 - sulfurous acid
  • HSO4 - hydrogen sulfate ion
  • H3PO- phosphoric acid
  • HNO- nitrous acid