8. (a) HA(aq) is a weak acid with a dissociation constant, Ka, of 8.8 x 10−12. What is the pH of a 0.022 M solution of A−(aq)? The temperature is 25 ◦C. (b)  For the reaction A(g) =A(l), the equilibrium constant is 0.666 at 25.0 ◦C and 0.222 at 75.0 ◦C. Making the approximation that the entropy and enthalpy changes of this reaction do not change with temperature, at what temperature will the equilibrium constant be equal to 0.777?

The active ingredient of bleach such as Clorox is sodium hypochlorite (NaClO). Its conjugate acid, hypochlorous acid (HClO), has a Ka of 3.0 × 10^–8. (a)  The undiluted bleach contains roughly 1 M NaClO. Calculate the pH of 1 M NaClO solution.  (b)  Some applications require extremely diluted bleach solution, such as swimming pools. Suppose the solution in (a) is diluted by 10,000 -fold. Calculate the pH of the diluted solution, and demonstrate that you can still neglect the autoionization of water in your calculation.  (c)  Suppose the solution in (a) is diluted by 1 million-fold, briefly explain how your approach will be different. Write the equation with [H3O+] as the unknown, but you do not need to solve it.

A solution is formed by adding 2.70 grams of solid sodium hypochlorite, NaClO, to 200.0 ml of 0.0210M calcium hypochlorite, Ca(ClO)₂. Calculate the pH of the resulting solution. You may assume that the sodium hypochlorite dissolve completely and that the change in volume is negligible with the addition of the solid.