Question

During mining operations, the mineral pyrite (FeS₂) is exposed to air and oxygen and reacts to produce sulfuric acid (H₂SO₄). The drainage from the Iron Mountain Mine in California was found to have [H₃O+] = 3.7 M. Calculate the pH of the water seeping from the mine.

Answer 1

To calculate the pH of mine water with a hydronium ion concentration of 3.7 M, use the formula pH = -log[H3O+], which results in a pH of approximately -0.568. This indicates an extremely acidic solution, similar to the conditions in Spain's Rio Tinto.

Step-by-step explanation:

The student has asked about calculating the pH of water seeping from the Iron Mountain Mine with a known concentration of hydronium ions [H3O+] of 3.7 M. To calculate the pH, we use the formula pH = -log[H3O+]. Applying the known concentration:

pH = -log(3.7 M)

When you calculate the logarithm of the hydronium ion concentration, you get:

pH ≈ -0.568

In this particular case, the pH is negative, indicating an extremely acidic solution, which is possible with such a high concentration of hydronium ions. It is important to understand that while the pH scale typically ranges from 0 to 14 for most solutions, it can indeed have negative values for very strong acids. The conditions described here are comparable to those in Spain's Rio Tinto, known for its acidic waters and unique ecosystems.