Colors on a universal indicator pH chart include: red, orange and yellow for acids, light green for neutral, and green, blue and violet for bases. The universal indicator chart assigns a color to each pH level on a scale of four to 10 pH.
A pH of four corresponds with the red color on the acidic end of the chart, while a pH of 10 corresponds with the violet color on the base end.
Universal indicator pH solution is used in conjunction with the chart. The solution has a neutral pH of seven, is light green in color and is diluted in water. When the solution is added to an acidic or basic chemical the color changes based on the pH of the chemical.