cabbage juice is a natural pH indicator
a pH indicator
Each indicator has a specific change of color when the pH is changed.
An indicator can provide exact pH if you are using the neutralization titration. Paper strip pH indicator are not an exact measurement but a high, medium, and low indication of acids and bases.
pH range of indicator should be in the rapid pH gradient.
ph-indicator strips (colorpHast)
The indicator is bromothymol blue.
Litmus paper will determine acid or base. Universal indicator paper (pH paper) will give an answer to the nearest whole number.
An example of an indicator would be Phenol Red, or Universal Indicator. Depending on the pH range of the indicator and the pH range of the substrates you would use the appropriate indicator.
indicator
Antacids have a pH under 7.
This is a pH indicator.