Hydrogen sulphide (a weak diprotic acid) is added to pure water at a concentration of 10- M. Assuming a temperature of 25 C and assuming ionic strength effects are negligible, determine the pH (to the nearest 0.01 pH) unit at equilibrium and the concentration of all species using: an exact solution. (5 marks) a. b. an approximate solution (Check your assumptions and compare the solution to the value obtained in part (a). That is, use the electroneutrality equation to check the percentage difference between the summation of cations versus anions) (5 marks)