Does lime or lemon have more citric acid?
"Lemon juice and lime juice are rich sources of citric acid, containing 1.44 and 1.38 g/oz, respectively."
PENNISTON, K. L., NAKADA, S. Y., HOLMES, R. P., & ASSIMOS, D. G. (2008). Quantitative Assessment of Citric Acid in Lemon Juice, Lime Juice, and Commercially-Available Fruit Juice Products. Journal of Endourology / Endourological Society, 22(3), 567–570. http://doi.org/10.1089/end.2007.0304
See also this Q&A for additional relevant information.