Finding the and pH of Basic Solutions

Finding the [OH ] and pH of a strong base solution is relatively straightforward, as shown in Example 15.11. As we did in calculating the [HjO ] in strong acid solutions, we can neglect the contribution of the autoionization of water to the [OH ] and focus solely on the strong base itself. 

Write the balanced equation for the ionization of water by the base and use it as a guide to prepare an ICE table showing the given concentration of the weak base as its initial concendation. Leave room in the table for the changes in concentrations and for the equilibrium concentrations. (Note that you should list the OH concentration as approximately zero. Although a little OH is present from the autoionization of water, this amount is negligibly small compared to the amount of OH formed by the base.) 

Represent the change in the concendation of OH with the variable x. Define the changes in the concentrations of the other reactants and products in terms of x. 

Sum each column to determine the equilibrium concendations in terms of the initial concentrations and the variable x. 

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