Question

Which of these pH numbers indicates the highest

level of acidity?
(1) 5 (3) 10
(2) 8 (4) 12

Answer 1

Acid pHs are anything below 7.
The only pH below 7 on that list is 5, so the answer is (1)
For GCSE, you need to know that the lowest pH you can get is 1

Answer 2

(1) 5 because it it below 7 and anything below ph 7 is acidic! Hope this helps you!! =')