Is there a difference in cytoplasmic pH between prokaryotes and eukaryotes?
In the article "pH of the Cytoplasm and Periplasm of Escherichia coli: Rapid Measurement by Green Fluorescent Protein Fluorimetry", by Jessica C. Wilks and Joan L. Slonczewski, the pH of E.coli cytoplasm was mentioned as 7.2 - 7.8. I just took E.coli's pH range as a common example of prokaryotes. 

Reference link: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1951819/