Ph measures how acidic or basic something is. The lower the number the more acidic it is going to be.
Drink A is basic, he can drink that
Drink B is neutral, he can drink that
Drink C is acidic, he should avoid
Drink D is basic, he can drink that
Drink E is acidic, he should avoid
I think its high. I just looked it up and it said stuff about how it is closely related to some gases.
Answer:
By making observations and doing experiments
Ammonia is the compound NH3