1-Aluminum sulfate is a coagulant used in water treatment. Aluminum quickly dissociates in water as follows:
Al2(SO4)3·14H2O ® 2 Al3+ + 3 SO4-2 + 14 H2O
(a) If 100 mg/L of aluminum sulfate is added to water and it completely dissolves, how many mmoles/L of Al3+ are present? How many mmoles/L of SO4-2?
(b) For the conditions given in part (b), how many milliequivalents/L of Al3+ are present? How many milliequivalents of SO4-2 are present?
(c) Al3+ is quickly hydrolyzed in water. The hydrolysis reaction is the following:
Al3+ + H2O ® Al(OH)+2 + H+
Does this reaction increase, decrease, or not change the pH?
2. If the pH of water is 6.8, what is the [H+] concentration?
If the [H+] concentration is 2x10-8 M, what is the pH?