Question

(Will give medal!!)

1. Calculate the hydrogen ion concentration (H+) for an aqueous solution in which [OH^-] is 1 x 10^-4 mol/L. Is the solution basic, acidic, or neutral?

2. What reaction is spontaneous for the following cell?
Ag+ + e- >>> Ag (E* = 0.80V)
Ba^2+ + 2e- >>> Ba (E+ = -2.90V)

Answer 1

For qn. 1, have you ever heard of the the equation [H+][OH-] = 1 * 10^(-14)?
The value at the end is K, the equilibrium dissociating constant of pure water (since it is neutral yo u will have equal concentrations of both ion in solution 1*10^-7, and this value is very small since water is really weak at dissociating).
By rearranging the formula and plugging in OH- concentration and rearranging, you will find the answer for H+ concentration. If you are not familiar with pH it is figuring out how acidic or basic a solution is, but using a logarithim scale. The general formula is pH= log [H+]. Use the concentration you got from the last step.

For qn. 2 reactions that have a do not have a positive reduction potential do not occur at standardized conditions because they require larger amounts of energy. Hope this leads you to your answer.