a contaminated water sample has a H of 3. How many times more acidic is this sample compared to neutral water of 7
For each gap of 1 on the pH scale, the pH becomes either 10x more acidic or basic depending on which direction you move in. In this case you will be come more acidic:
7-6 = 10x
7-5 = 100x
7-4 = 1000x
7-3 = 10,000x more acidic