1. What is the oxidation number of Sulfur in the ionic compound K2SO4? Explain.
2. The solubility of Mg(OH)2 Salt increases by decreasing the pH. Explain by writing chemical reactions.
3. When KBr (Potassium Bromide) added to pure water, the pH will not change. Why?
4. A second-order reaction has a half-life of 18s when the initial concentration of reactant is 0.71 M.
a) Calculate the rate constant for this reaction.
b) How long of time (in seconds) will it take for the initial concentration to drop from 0.71 M to 0.5 M?
c) What is the half-life of the reaction, if one starts with 0.1 M solution?