Equilibrium Constant and Free EnergyΔG=-RTln(Ka)Chlorine Chemistry: Free Chlorine (Cl2 (aq),HClO,ClO-)When pH is less than 2, dominant species is Cl2 (aq)When pH is greater than 2, dominant species are HClO and ClO-HClO has 100 times the disinfection power of ClO-Chlorine Chemistry: ChloraminesNH2Cl-monochloramineNHCl2-dichloramineNCl3-trichloramineIf [Cl2]dose/[NH3]dose is<1.5 then chloramines are in the solutionIf = 1.5, this is the breakpointCl2+NH3 N2+Cl-There is no disinfection power at this pointIf>1.5, then we have free chlorines[Cl2]consumed=1.5*[NH3]dose[Cl2]residual=initial-consumed=amount of free chlorine, species depending on pHRedox RulesH always has an oxidation state of +1O always has -2Redox and Disinfection 04/24/2012Equilibrium Constant and Free Energy- ΔG=-RTln(Ka)Chlorine Chemistry: Free Chlorine (Cl2 (aq),HClO,ClO-)- When pH is less than 2, dominant species is Cl2 (aq)- When pH is greater than 2, dominant species are HClO and ClO-- HClO has 100 times the disinfection power of ClO-Chlorine Chemistry: Chloramines- NH2Cl-monochloramine- NHCl2-dichloramine- NCl3-trichloramine- If [Cl2]dose/[NH3]dose is o <1.5 then chloramines are in the solutiono If = 1.5, this is the breakpoint Cl2+NH3 N2+Cl- There is no disinfection power at this pointo If>1.5, then we have free chlorines- [Cl2]consumed=1.5*[NH3]dose- [Cl2]residual=initial-consumed=amount of free chlorine, species depending on pHRedox Rules- H always has an oxidation state of +1- O always has