If you are want to Build a circuit where you can detect the ph factor of liquid, whether it is basic or alkaline.
This is a Liquid pH Value Detection Sensor for Arduino. This is used in water quality testing and Aquaculture
The pH stands for the power of hydrogen, which is a measurement of the hydrogen ion concentration in the body.
The total pH scale ranges from 1 to 14, with 7 considered to be neutral.
A pH less than 7 is said to be acidic and solutions with a pH greater than 7 are basic or alkaline.
The PH electrode has a single cylinder that allows direct connection to the input terminal of a pH meter, controller, or any pH device which has a BNC input terminal.
The pH electrode probe is accurate and reliable that can give almost instantaneous readings.