The painkiller, Advil® contains the active ingredient ibuprofen (IB), which has a pKb of 5.20. If the pH of a solution containing a dissolved tablet of Advil® was found to be
8.20, what was the equilibrium concentration (mol/L) of ibuprofen?

IB + H2O ⇀ IBH+ + OH−

A) 3.7 × 10−4
B) 5.5 × 10−5
C) 2.8 × 10−7
D) 4.0 × 10−7
E) 9.2 × 10−7

In a ni-cd battery, a fully charged cell is composed of nickelic hydroxide. nickel is an element that has multiple oxidation states. assume the following proportions of the states: nickel charge proportions found 0 0.17 +2 0.3 +3 0.33 +4 0.5 (a) determine the mean of the nickel charge. enter the answer to 2 decimal places.(b) determine the cumulative distribution function of nickel charge.