91Ó°ÊÓ

20-36 Order the compounds in each of the following sets with respect to increasing acidity:

(a) Acetic acid, oxalic acid, formic acid

(b) p-Bromobenzoic acid, p-nitrobenzoic acid, 2,4-dinitrobenzoic acid

(c) Fluoroacetic acid, 3-fluoropropanoic acid, iodoacetic acid

Arrange the compounds in each of the following sets in order of increasing basicity:

(a) Magnesium acetate, magnesium hydroxide, methyl magnesium bromide

(b) Sodium benzoate, sodium p-nitrobenzoate, sodium acetylide

(c) Lithium hydroxide, lithium ethoxide, lithium formate

Calculate the pK_a's for the following acids:

(a) Lactic acid, Ka = 8.4 × 10^-4

(b) Acrylic acid, Ka = 5.6 × 10^-6

Calculate the K_a's for the following acids:

(a) Citric acid, pKa = 3.14

(b) Tartaric acid, pKa = 2.98

Assume you have a mixture of naphthalene and benzoic acid that you want to separate. How might you take advantage of the acidity of one component in the mixture to effect a separation?

Thioglycolic acid, HSCHâ‚‚COâ‚‚H, a substance used in depilatory agents(hair removers) has pKa = 3.42. What is the percent dissociation ofthioglycolic acid in a buffer solution at pH = 3.0?

Thioglycolic acid, ${\mathbf{HSCH}}_2{\mathbf{CO}}_2\mathbf{H}$, a substance used in depilatory agents
(hair removers) has$\mathbf{pKa}\mathbf{=}\mathbf{3}\mathbf{.}\mathbf{42}$. What is the percent dissociation of
thioglycolic acid in a buffer solution at $\mathbf{pH}\mathbf{=}\mathbf{3}\mathbf{.}\mathbf{0}$?

In humans, the final product of purine degradation from DNA is uricacid, pKa = 5.61, which is excreted in the urine. What is the percent dissociation of uric acid in urine at a typical pH = 6.0? Why do you think uric acid is acidic even though it does not have a COâ‚‚H group?

In humans, the final product of purine degradation from DNA is uric acid, $\mathbf{pKa}=\mathbf{5}.\mathbf{61}$, which is excreted in the urine. What is the percentdissociation of uric acid in urine at a typical $\mathbf{pH}\mathbf{=}\mathbf{6}\mathbf{.}\mathbf{0}$? Why do you think uric acid is acidic even though it does not have a ${\mathbf{CO}}_2\mathbf{H}$group?

In humans, the final product of purine degradation from DNA is uric acid, pKa = 5.61, which is excreted in the urine. What is the percent dissociation of uric acid in urine at a typical pH = 6.0? Why do you think uric acid is acidic even though it does not have a COâ‚‚H group?