Your skin's natural pH is around 5.5. But pollution, oil production, makeup, and alcohol can shift your skin's state, hence its pH. K-Beauty toners, on the other hand, mimic the skin's natural pH.5.5 might be normal but its slightly acidic. Which is normal if you say so, I dont know.
7 is neutral, the scale is 1 to 14. Low numbers acid, high numbers alkaline.
https://www.google.com/search?q=wha...aIAYkGkgECMTCYAQCgAQHIAQrAAQE&sclient=gws-wiz