The following scenes represent three weak acids HA (where

Problem 18.189

The following scenes represent three weak acids HA (where A ?X, Y, or Z) dissolved in

water ( is not shown):

[HCIO] [HCIO] (CIO) C12(aq) 2H20(1) HCIO(aq) H30(aq) Cl(aq) The first step the reaction of an amine with an acid chloride is HX HY HZ HA =  = A = (a) Rank the acids in order of increasing ka. (b) Rank the acids in order of increasing pka. (c) Rank the conjugate bases in order of increasing pKb. (d) What is the percent dissociation of HX? (e) If equimolar amounts of the sodium salts of the acids (Nax, Nay, and Naz) were dissolved in water, which solution would have the highest pOH? The lowest pH? CHC

                                                             Step by Step Solution

Step 1 of 5

All the scenes represent same initial concentration of each acid; they are HX, HY. and HZ

respectively. Greater the concentration of  for an acid, greater is the value of the acid-dissociation constant, .

(a)

There are two  ions in HX, six  ions in HY, and four  ions in HZ. The concentration of  is highest for HY and lowest for HX So, HY has the highest value of the acid-dissociation constant  while hx has the lowest value of the acid-dissociation constant .

Therefore, the order of acids increasing with their  values is HX<HZ<HY.

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