Question

Answer all of the questions please. Not due until 2-27-19

0 A substituted 1,2-diphenyl ethanone (pK-17.3) is dissolved in organic solvent dimethylsulfoxide (DMSO) and treated with equimolar amount of a substituted potassium phenolate (R-CgH4OK) as a base (pka of the substituted phenol in DMSO equals 16.7). Calculate percent ionization (deprotonation) of carbonyl containing compound. Round your answer to the nearest tenth decimal, e.g. 1.1, don't add percent sign to your answer. (deprotonation) ad percent sian to your anwe Answer What percentage of acetylacetone (pKa - 9.0) will be found in deprotonated form at pH-8? Select one: O a, 9196 O b. 6196 С. 9% O d. 33% O e. 10096

Answer 1

For percentage ionization or deprotonating Consider HA is an acid HA + H_2 O equilibrium [H_3O^+] + A^- Let initial ionic: 100M 0 0 at equilibrium: 100 - x x x Vertical-bar Vertical-bar lly for acetyl accetenane, pKa = 9.0 = > - log ka = 9.0 = > ka = 10^-9 and pH = 8 - log H^+ = 8 [H^+] = 10^-8 Ka, is dissociation constant of acetyl action ie Ka = [H^+][A^-]/[HA] 10^-9 = 10^-8 times x 100 - x 1/10 = x/100 - x 100 - x = 10 x 11x = 100 = > x = 9.09 almostequalto 9.1 Therefore % age of deprotonated acid (A/HA times 100) = 9.1/100 times 100 = 9.1% almostequalto 9% anw (C)