Does the Cheshire Cat evaporate

Answer 1

The word 'evaporate' describes a change in state from liquid to vapour. As the Cheshire Cat is at no time a liquid (at least, not while we're looking at him) he cannot evaporate.

It might be better to ask 'does the Cheshire Cat sublime?' as, in chemistry, the word 'sublime' means to change directly from a solid to a vapour or gas.

We don't know whether the Cheshire Cat is in fact, at any point, a gas, but Lewis Carroll never says that he isn't.

(So, once he reappears, it might be fair to say that the Cheshire Cat has gone from the sublimate to the ridiculous.)

Answer 2

In "Alice's Adventures in Wonderland," the Cheshire Cat is known to disappear or vanish at will, rather than physically evaporate like a liquid. The character's ability to appear and disappear with only its grin remaining is one of its defining traits in the story.