I made a saline solution of NaCl 0,9% andajusted the pH to 11 with NaOH. After 3 months I read the Ph and it had come down to 8. Does anyone know why?

I've also made a saline solution of NaCl 0,9% pH 9 and after 3 months it came down to pH 5. I don't understand why the pH came so drastcally down. I tested for any contamination and the results...

18 December 2018 8,865 3 View