One step in the processing of cucumbers to pickles is the pickling process itself. In one method of making pickles, young cucumbers with no waxy skins are soaked in a NaC1 solution overnight. To initiate the pickling process, acetic acid is added to the salt solution to make the pickling brine. The acetic acid acts as a preservative, and the salt solution keeps the cucumber from swelling as the acetic acid diffuses into the cucumber. When a certain concentration of acetic acid inside the cucumber is achieved, the cucumber is considered “pickled” and will remain safe and tasty to eat for a long time. In the present pickling process, the temperature is 80^oC, and the pickling brine solution contains an acetic acid concentration of 0.900 kgmole/m³. The cucumbers are 12.0 cm in length and 2.5 cm in diameter. The amount of cucumbers relative to the amount of pickling brine solution is small so that the bulk liquid-phase concentration of acetic acid remains essentially constant during the pickling process. Initially, the cucumbers do not contain any acetic acid, and are maintained at 80°C. End effects can be neglected. It can also be assumed that the diffusion coefficient of acetic acid into the pickle approximates the diffusion coefficient of acetic acid in water. The diffusion coefficient of acetic acid in water at 20°C (not 80°C) is 1.21 × 10^-5 cm²/s.