91Ó°ÊÓ

Draw structures corresponding to the following IUPAC names: (a) 2,3 -Dimethylhexanoic acid (b) 4 -Methylpentanoic acid (c) trans-1,2-Cyclobutanedicarboxylic acid (d) \(o\) -Hydroxybenzoic acid (e) \((9 Z, 12 Z)-9,12\) -Octadecadienoic acid (f) 2 -Pentenenitrile

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?

The \(K_{\mathrm{a}}\) for dichloroacetic acid is \(3.32 \times 10^{-2}\). Approximately what percentage of the acid is dissociated in a \(0.10 \mathrm{M}\) aqueous solution?

Calculate the percentages of dissociated and undissociated forms present in the following solutions: (a) \(0.0010 \mathrm{M}\) glycolic acid \(\left(\mathrm{HOCH}_{2} \mathrm{CO}_{2} \mathrm{H} ; \mathrm{p} K_{\mathrm{a}}=3.83\right)\) at \(\mathrm{pH}=4.50\) (b) \(0.0020 \mathrm{M}\) propanoic acid \(\left(\mathrm{p} K_{\mathrm{a}}=4.87\right)\) at \(\mathrm{pH}=5.30\)

Which would you expect to be a stronger acid, the lactic acid found in tired muscles or acetic acid? Explain.

Dicarboxylic acids have two dissociation constants, one for the initial dissociation into a monoanion and one for the second dissociation into a dianion. For oxalic acid, \(\mathrm{HO}_{2} \mathrm{C}-\mathrm{CO}_{2} \mathrm{H},\) the first ionization constant is \(\mathrm{pK}_{\mathrm{a} 1}=1.2\) and the second ionization constant is \(\mathrm{p} K_{\mathrm{a} 2}=4.2 .\) Why is the second carboxyl group far less acidic than the first?

The \(\mathrm{p} K_{\mathrm{a}}\) of \(p\) -cyclopropylbenzoic acid is \(4.45 .\) Is cyclopropylbenzene likely to be more reactive or less reactive than benzene toward electrophilic bromination? Explain.

Rank the following compounds in order of increasing acidity. Don't look at a table of \(\mathrm{p} K_{\mathrm{a}}\) data to help with your answer. (a) Benzoic acid, \(p\) -methylbenzoic acid, \(p\) -chlorobenzoic acid (b) \(p\) -Nitrobenzoic acid, acetic acid, benzoic acid

How would you prepare the following carboxylic acids? (a) \(\left(\mathrm{CH}_{3}\right)_{3} \mathrm{CCO}_{2} \mathrm{H}\) from \(\left(\mathrm{CH}_{3}\right)_{3} \mathrm{CCl}\) (b) \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CO}_{2} \mathrm{H}\) from \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{Br}\)

How might you prepare 2 -phenylethanol from benzyl bromide? More than one step is needed.