Isobutylamine is a weak base. If the initial concentration of isobutylamine is 0.055 M and teh equilibrium concentration of OH is 4.0 x 10 -3 M, calculate Kb for isobutylamine.

16-27 Guanidine, p/Ca 13.6, is a very strong base, almost as basic as hydroxide ion. NH NH2+ II II H2N—C—NH2 + H2O H2N—C—NH2 + OH" Guanidine Guanidinium ion pKb = 13.6 Complete the Lewis structure for guanidine, showing all valence electrons. The remarkable basicity of guanidine is attributed to the fact that the positive charge on the guanidinium ion is delocalized by resonance over the three nitrogen atoms. This delocalization increases the stability of the guanidinium ion relative to the ammonium ion or substituted ammonium ions. Draw three equivalent contributing structures for the guanidinium ion and show by the use of curved arrows how these three contributors are related. Propose an explanation for the fact that protonation occurs on the C=NH nitrogen rather than on one of the —NH., nitrogens. (Hint: Consider the resonance stabilization of the structure formed by protonation on a —NH., nitrogen compared with the resonance stabilization of the structure formed by protonation on the =NH nitrogen.) Predict the N—C—N bond angles in the hybrid. Which is the stronger acid, the ammonium ion or the guanidinium ion?

Calculate the pH of a 0.0200M solution of ibuprofen (isobutylphenylpropionic acid, C,2H17COOH) solution at 25 °C given that it's conjugate base, isobutylphenylpropionate, has a Kp = 2.7 x 10-10 %3D 2.565 11.268 O6.130 O5.634 O 3.065

Consider the following data on some weak acids and weak bases: acid base Ba K, name formula name formula hydrocyanic acid HCN 10 4.9 x 10 methylamine| CH3NH2 |4.4 × 10 HCH,CO2 1.8 × 10 ethylamine C2H5NH2|6.4 × 10 acetic acid Use this data to rank the following solutions in order of increasing pH. In other words, select a '1' next to the solution that will have the lowest pH, a '2' next to the solution that will have the next lowest pH, and so on. solution pH 0.1 M NaCN choose one 0.1 M KBr choose one 0.1 М КСН3СО2 choose one 0.1 М CН3NHзBr choose one