A solution that is a 4 on th e pH scale is a

A pH scale is a scale ranges from 1 to 14. In the pH scale 1 to 7 shows the acidic condition and 7 to 14 shows the basic condition. The acidity increases from 1 to 7 and basicity increases from 7 to 14 on the pH scale. Here 7 on a pH scale is the neutral value. Hence a solution having value 4 on a pH scale is an acid.

It's an acid if it has that pH