While watching friends make soap this afternoon, a question arose.
When dissolving solid NaOH in distilled water in a stainless-steel pot, we place the pot in a sink of cold water to prevent excessive heating due to the exothermic reaction. When using a different pot which is stainless steel but also has a slab of Cu bonded to the bottom to facilitate even heating, the NaOH tends to not dissolve evenly or really at all, but to change from a pile of pellets to a fused mass forming a coating that pretty much sticks to the bottom of the pot. The only difference is the thermal conductivity of the two pots' bases, but I fail to come up with a mechanism to explain the different behaviors.
Any suggestions out there?