Table 1. pK Values of substituted benzoic acids in aqueous ethanol solution.

Temperature = 25.0 ± 0.2 °C.

Substituent	Weight percent ethanol in solution
	0.0				12.2				25.2				44.1				64.8
	na	pKapp.	$S/\sqrt{n}$b	pKcor.c	n	pKapp.	$S/\sqrt{n}$	pKcor.	n	pKapp.	$S/\sqrt{n}$	pKcor.	n	pKapp.	$S/\sqrt{n}$	pKcor.	n	pKapp.	$S/\sqrt{n}$	pKcor.
Hydrogen	17	4.210	0.002	4.210	14	4.444	0.002	4.46	16	4.918	0.003	4.89	8	5.692	0.004	5.55	15	6.424	0.012	6.21
m-Allyl	9	4.266	.004	4.266	8	4.514	.007	4.53	4	5.035	.010	5.01	5	5.808	.003	5.66	4	6.532	.009	6.32
p-Allyl	9	4.326	.004	4.326	8	4.563	.003	4.58	5	5.061	.007	5.04	3	5.811	.003	5.67	3	6.537	.013	6.32
m-Propenyl	5	4.248	.006	4.248	7	4.485	.007	4.50	4	4.972	.001	4.95	7	5.763	.008	5.62	2	6.478	.008	6.26
p-Propenyl	4	4.487	.003	4.487	3	4.785	.039	4.80	4	5.154	.016	5.13	2	5.854	.014	5.71	6	6.614	.028	6.40

^an = number of runs.

^bStandard error of the mean = $\frac{S}{\sqrt{n}}.$

Estimated standard deviation = $\sqrt{\frac{n\sum x^2-{\left(\sum x\right)}^2}{n\left(n-1\right)}}.$

^cpK_cor. is corrected for liquid junction potential and the medium effect for hydrogen ion; pK_cor. = pK_app. – δ.