Question

How will the pH of brine will be affected when it is electrolysed ?

Answer 1

while some reactions do produce a change in pH, others don't involve the acidity of the solution. The essence here is that, you've got to consider the equilibrium, if you're adding energy to produce the pH change, that is the energy affects the pH directly, than obviously you can model the situation to the experiment. If you are to produce any reactions which results in acid and base agents, so to speak, you'll have changes in pH. As for whether the direct electrical energy, somehow, alters the state of the autoprotolysis of water completely, upon reaching equilibrium, I'm not sure how that could work. If you were to change the temperature, the pH may change. Simply, a lot of factors affect the pH, but you should first consider the chemicals involved and then model the system.

Reference https://www.physicsforums.com/threads/ph-and-electrolysis.113766/

Answer 2

Hey !!

Aqueous solution of brine contains Na⁺ , Cl⁻ , H⁺ and OH⁻

2H⁺ + 2e⁻ -----> H₂ (At Cathode)

2Cl⁻ -----> Cl₂ + 2e⁻ (At anode)

The remanining solution contains NaOH, which is a base, therefore pH will increase.

Good luck !!