pH vs Chloride

[engfa]

what is the relationship between pH and Chloride when it comes to corrosion?

 

[moltenmetal]

Low pH and high Cl- is bad.

Want to know more? What material are we talking about? What else is in the water, other than H+, OH- and Cl-? What temperature range?

 

[bimr]

Yes, a lower pH and a higher chloride concentration will generally be more corrosive, but it depends on what else is in the fluid as well as the materials of construction.

Don't believe that there is a relationship between pH and chloride. Chloride is an ionic compound usually associated with sodium in water which does not affect the pH. However, when chloride is associated with hydrogen as in hydrochloric acid, the pH will be lowered.

 

[zdas04]

I agree with the other posts. In Oil & Gas I regularly see water with over 50,000 mg/L of chloride and pH of greater than 7.0. Ocean water tends to be slightly basic. The energy of formation favors chloride hooking up with sodium or magnesium to form salts rather than with free hydrogen to form acids.

David Simpson, PE
MuleShoe Engineering

In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. Galileo Galilei, Italian Physicist