What is the pH of cytosol? And plastids?
The optimum cytoplasmic pH for performing physiological activities in
plant cells is a neutral pH of around 7.2 to 7.4.
The pH of apoplastic space outside plasma membrane and vacuolar pH is
acidic ranging between 5 to 7.
The thylakoid lumen is more fluctuating which varies during light /
dark cycles and is highly acidic.
The mitochondrial compartment and chloroplast maintains a basic
conditions of about pH 8 for optimization of biochemical reactions
occurring in these two particular compartments.

(Via: https://www.frontiersin.org/articles/10.3389/fpls.2017.02079/full#:~:text=Plastid%20stromal%20pH%20could%20only,cytosolic%20pH%20(around%207.3).