Answer:
A. 3 x 10-12
Explanation:
Generally, the parts-per notation is used to represent very small concentration without any specific unit.
Parts per million is notated as 
Parts per billion is notated as 
Parts per trillion is notated as 
Hence, 3 parts per trillion will be written as 3 x 
The correct option is A.
C because it is and I know
Answer:
The range of [H⁺] is from 2.51 x 10⁻⁶ M to 6.31 x 10⁻⁶ M,
Explanation:
To answer this problem we need to keep in mind the <u>definition of pH</u>:
So now we <u>calculate [H⁺] using a pH value of 5.2 and of 5.6</u>:
-5.2 = log [H⁺]
= [H⁺]
6.31 x 10⁻⁶ M = [H⁺]
-5.6 = log [H⁺]
= [H⁺]
2.51 x 10⁻⁶ M = [H⁺]
33.6 moles are needed to completely react with 84.0 moles of O2