Many people do not know what pH represents, but those who do know that purified water has a neutral one. “P” in pH means power, and “H” – hydrogen.
These two letters represent an equation of hydrogen ion concentration. This equation defines if a certain substance is acidic or alkaline. This range starts from 0 and goes to 14. 7 is the neutral number and this is what distilled water should measure at. If the numbers are lower than 7, then the substance is acidic, and it is alkaline when over 7.
The number 7 in distilled water means that it consists purely of hydrogen and oxygen. But this water absorbs things from the outside, because when it goes under this purification it becomes very aggressive and strives to go back to its original state. So this water will most likely absorb carbon dioxide that is in the air, which will make it slightly acidic.
Add 1/8 tablespoon of baking soda to one gallon of this water, and you will make it neutral again. The baking soda has a pH of 8. If the pH of a liquid is very low, it is very acidic and poisonous, like hydrochloric acid for example. Same goes if the numbers are too high, then the substance is alkaline and is also poisonous – ammonia for instance is 12.
Purified water is exactly what you need – pure pH neutral liquid.