It is the difference is that "what" in a question has unlimited choices: What is your name? while "which" has a limited amount of two or more choices, and the person asking usually knows what the choices are: Which is your favorite color? Hope this helps. : )

So, the correct sentence is "Wich is the difference between wich and what? " isn´t it?

which is cual what is que

Which- refers to a closed set: 'Which of these do you want?' You couldn't replace this with 'what'. There are cases where there isn't much difference, but where the choice is clearly restricted, then 'which' would be the better choice. You use "Which" when you must to choose between options; For example: "Which color do you prefer?"

The main difference is: You use "Which" when you must to choose between options; For example: "Which color do you prefer?"