Is d3-acetic acid more acidic than acetic acid?
The following articles suggest that the data reported from Solomons, Fryhle and Snyder Organic Chemistry is likely incorrect.


Maya Paabo, Roger G. Bates and R. A. Robinson ("Dissociation of Acetic Acid-d3 in Aqueous Solution and Related Isotope Effects from 0 to 50°", J. Phys. Chem. 1966, 70, 2, 540-543) report that the $\mathrm{p}K_\text{a}$ of the deuterioacid is greater (less acidic) than that of the protio analogue.
See Table 1 on p. 134 of C. L. Perrin's chapter ("Advances in Physical Organic Chemistry", Volume 44, edited by John P. Richard) where it is also reported that the $\mathrm{p}K_\text{a}$ of the deuterioacid is greater (less acidic) than that of the protio analogue.
Rose McConnell, Walter Godwin, Brant Stanley, and M.Shane Green ("Acidity Studies of Deuterated Acids and Bases Commonly Used as Buffers in NMR Studies", Journal of the Arkansas Academy of Science, Volume 51 Article 21) also report (see Table 1 on p. 140) similar findings.


These findings indicate that acetic acid-d3 is less acidic than acetic acid-h3.  This would be consistent with the operation of a simple inductive effect where protium is more electronegative than deuterium (as expected).  Hence, the more electron withdrawing $\ce{CH3}$ group is better able to stabilize the electron rich carboxylate anion in the the ionized acid as compared to the less electron withdrawing $\ce{CD3}$ group.