begin mathsize 48px style p H space equals space minus log left square bracket H to the power of plus right square bracket almost equal to negative log C end style

 C = Concentration of a monobasic Acidic Soluiton or Concentration of H+ due to the acid ; pH = -log[H+] ; [H+]= Hydrogen Ion Concentration




The ionization of an acid in water measures the relative strength of the acid. For strong acids practically 100% of the acid is dissociated. Thus essentially the concentration of the H+ ion is equal to the acid concentration. However, when acid concentration is very low, we must consider the hydrogen ions of water too. We know that hydrogen ion concentration exclusively from water is 10-7 mol/L at 25oC. In such case, we must add this quantity to the concentration of acid, i.e , for dilute system pH = -log( C + 10-7) . However when C is large enough we can omit the hydrogen ion concentration from water. The above calculator works well for dilute as well as concetrated strong acids. Examples of strong acids include HCl ,  HNO, HBr, HI , HClO etc. It must be noted that this equation is only valid with acids containing one strongly protonable hydrogen.  
Thanks to Bennett Haselton of for his valuable inputs to improve this calculator. 

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