Concept:Lemon juice contains citric acid, so it is acidic. The pH scale measures acidity: lower pH means stronger acid.
Explanation:Acidic substances have a pH less than 7.
Lemon juice is a common acidic substance.
From standard pH data, lemon juice has a pH in the range of 2 to 3.
This range indicates a strong acid.
Among the options: 3.8, 5.5, 6.6, and 2.5, only 2.5 falls in the 2–3 range.
So lemon juice pH is approximately 2.5.
Answer:Option D. 2.5