[scientizscht (OP)]

Hello

What are the methods to detect that a chemical reaction is taking place without having to get a sample from the solution?

The reaction will consume a neutral substrate and it will produce an acid which will dissociate into a proton and a negatively charged ion but the overall pH will not change due to buffering.

Is it possible to identify that such reaction is taking place, e.g. by measuring the magnetic or electric field or any other way?

Thanks!

[Bored chemist]

It's another of your "too wide to be useful" questions.

Pick a property- temperature, density, refractive index, conductivity, optical absorption or just about anything else.
It's likely that it will change during a reaction.
Why do you keep asking questions like this?