Calculate the pH of a 0.154 M solution of ethylenediamine (H,NCH2CH2NH2). The pKa values for the acidic form of thylenediamine (H3NCH2CH2NH) are 6.848 (pKa1) and 9.928 (pKa2). pH = 11.51 Correct Answer Calculate the concentration of each form of ethylenediamine in this solution at equilibrium. [H2NCH2CH2NH] = 4.12 x10-3 Incorrect Answer 7.05 x10 -8 [HNCH2CH2NH] = Correct Answer M M

Acid-Base Equilibria Many factors contribute to the acidity of organic compounds. Electronegativity, resonance, induction, hybridization, aromaticity, and atomic size, all play a role. In the following comparisons, you are asked to identify the factor(s) that would be most important to analyze when predicting relative acidity, and then to predict the trend in acidity and pKa values. For each of the following pairs of compounds answer the following two multiple-choice questions. 1. What factor(s) are the most important to consider when predicting the relative acidity of the two compounds? a. Electronegativity of the atom possessing the hydrogen. b. Resonance stabilization of the anionic conjugate base. c. Inductive stabilization of the anionic conjugate base. d. Hybridization of the atom possessing the hydrogen. e. The atomic size of the atom possessing the hydrogen.

Calculate the pH of a 0.123 M solution of ethylenediamine (H₂NCH₂CH₂NH₂). The pKą values for the acidic form of ethylenediamine (H3NCH₂CH₂NH³) are 6.848 (pKal) and 9.928 (pKa2). pH = Calculate the concentration of each form of ethylenediamine in this solution at equilibrium. [H₂NCH₂CH₂NH₂] : = [H₂NCH₂CH₂NH3] = M M

Calculate the pH of a 0.295 M solution of ethylenediamine (H₂NCH,CH,NH₂). The pKa values for the acidic form of ethylenediamine (HNCH,CH,NH) are 6.848 (pKa1) and 9.928 (pKa2). pH = Calculate the concentration of each form of ethylenediamine in this solution at equilibrium. [H2NCH2CH2NH₂] = [H2NCH,CH,NH] = [HNCH,CH,NH3] = M M M