Can the Therma 1 withstand immersion in a chemical like acid?

Clearly the Therma 1 main unit is not intended to be immersed in any liquid. The K type probes are quite robust and mostly made from stainless steel. They would probably survive most corrosive liquids at least for a short time. I would not recommend that any of the K type probes be left in corrosive liquiids for long periods. It may be possible in some applications to use a thin wire probe and fix it with an adhesive pad to the side of the container avoiding any contact with the corrosive material.