A sample of water has hardness expressed as 81 ppm Ca2+(aq). The sample is passed through an ion exchange column and the Ca2+(aq) ions are replaced by H+(aq) ions. What is the pH of the water after it has been treated? (1 ppm = 1 g solute/106 g solution)
◦ 2.50 ppm
◦ 1.10 ppm
◦ 0.79 ppm
◦ 2.39 ppm
◦ 2.70 ppm