All my classical chem. texts say, in essence, pure water has a Ph of 7.0. Also, pure water may be obtained by distillation.

 

My book on building a live steam locomotive, under boiler care, claims distilled water has a Ph of about 5.5! (??). That's what started my wheels turning. I bought steam distilled water from 3 different sources; all checked out acidic, one as low as 5.0. That's low enough to corrode my boiler tubes!

 

Obviously, the Ph is easily adjusted upward, probably with baking soda. However, can someone come up with an explanation whether the texts are wrong, or something funny is going on with the distilled water?

 

(Textbooks CAN be wrong. My calculus text claims pistons in an automotive engine move in Simple Harmonic Motion. They don't). Thanks for your input! Imp.

Distilled water invariably contains dissolved CO2