Final answer:
Lemon juice is the strongest acid among the given options due to its lowest pH value of 2, making it significantly more acidic than orange juice, vinegar, or soda pop.
Step-by-step explanation:
Among vinegar, soda pop, orange juice, and lemon juice, lemon juice is the strongest acid. This is due to its lowest pH value which is 2. In terms of acidity, the pH scale is logarithmic, meaning each whole pH value below 7 is ten times more acidic than the next higher value. Therefore, lemon juice with a pH of 2 is significantly more acidic than orange juice with a pH of 4, making it 100 times more acidic.
Vinegar contains acetic acid, which is a weak acid. Soda pop contains phosphoric acid which is stronger than acetic acid but still less strong than the citric acid found in lemon juice. Orange juice also contains citric acid, however, since its pH is higher than that of lemon juice, it is less acidic and thus, a weaker acid in comparison.