How many times stronger is the hydrogen-ion concentration of a pH 4 solution as compared with a pH 9 solution?
0.00001
5
100,000
50
Correct Answer : C
The correct answer is c. 100,000. The pH scale is a logarithmic scale, which means that each change of one pH unit represents a tenfold change in the hydrogen-ion concentration. A pH 4 solution has a hydrogen-ion concentration that is 10^5 (or 100,000) times greater than that of a pH 9 solution.
a. 0.00001 is the hydrogen-ion concentration of a pH 9 solution as compared with a pH 4 solution.
b. 5 is the difference in pH units between a pH 4 solution and a pH 9 solution.
d. 50 is not the correct answer.
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