Which of the following processes is affected by alkalinity in rayon fibers?

The process that is most affected by alkalinity in rayon fibers is coloring. Rayon, being a regenerated cellulose fiber, can be sensitive to pH levels. High alkalinity can lead to degradation or alteration in the fiber structure, which impacts its ability to hold dyes. As a result, if the colorants are applied in an environment with elevated alkaline levels, the dyes may not adhere properly or may produce unexpected color results.

When considering the other processes, while washing and spotting may also be influenced by the chemical properties of the detergent or cleaning solutions used, they are less directly impacted by alkalinity than the coloring process. Drying, on the other hand, relates more to moisture removal rather than chemical interactions influenced by pH, making it less relevant in this context. Thus, the sensitivity of rayon fibers to alkaline conditions during dyeing makes the coloring process the most affected.