The pH of a sample of water from a river is 6.0.A sample of effluent from a food processing plant has a pH of 4.0.The concentration of hydronium ion in the effluent is
A)one and a half times (1.5x)larger than the river hydronium ion concentration.
B)two times (2x)larger than the river hydronium ion concentration.
C)four times (4x)larger than the river hydronium ion concentration.
D)100 times (100x)larger than the river hydronium ion concentration.

Question

Quizplus · Accepted Answer

The pH of the effluent is two units lower than the river water pH (pH = -log[H+]). Each unit decrease in pH corresponds to a tenfold increase in [H+]. So, the concentration of hydronium ion in the effluent is 10^2 times (100x) larger than in the river water (10^-6 vs 10^-4). Therefore, the answer is D.

The PH of a Sample of Water from a River