Question

Public Health Service standards for drinking water set a maximum of 250 mg/L (2.60 × 10⁻³ M) of SO₄²⁻ because of its cathartic action (it is a laxative). Does natural water that is saturated with CaSO₄ ("gyp" water) as a result of passing through soil containing gypsum, CaSO₄·2H₂O, meet these standards? What is the concentration of SO₄²⁻ in such water?

a) Yes, 1.0 × 10⁻³ M
b) No, 3.0 × 10⁻⁴ M
c) Yes, 5.0 × 10⁻⁶ M
d) No, 2.0 × 10⁻² M

Answer 1

No, the concentration of SO₄²⁻ in gyp water does not meet the Public Health Service standards for drinking water.

Step-by-step explanation:

The concentration of SO₄²⁻ in gyp water can be determined by comparing it to the Public Health Service standards for drinking water which set a maximum of 250 mg/L (2.60 × 10⁻³ M) of SO₄²⁻. The concentration of SO₄²⁻ in gyp water is higher than the maximum allowed concentration, so it does not meet the standards. Therefore, the correct answer is No, 2.0 × 10⁻² M.