Chapter 22, Problem 100IAE

Refer to the Integrative Example on page 1082. Assume that the disproportionation of $\left[S_2{O}_3{}^{2-}\right]$ is no longer spontaneous when the partial pressure of $S{O}_z\left(g\right)$ above a solution with $\left[S_2{O}_3{}^{2-}\right]=1M$ has dropped $1\times {10}^{-6}atm$ . Show that this condition is reached while the solution is still acidic.