Question

Choose the most acidic substance in the group.

lemon juice, pH = 2.25

orange juice, pH = 3.75

milk, pH = 6.6

seawater, pH = 8

Answer 1

Lemon juice (pH 2.25) is the most acidic. Lower pH means higher H+ concentration — for example, it's about 10^(3.75−2.25) ≈ 31.6 times more acidic than orange juice.