Answer :

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

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