I am creating chatbot application using MS bot framework. In that, I want to disable both buttons once Yes or No is clicked.
Sorry but the webchat (and other channels) does not support what you want to do, even if it would be useful for many cases.
There is a sort of workaround if you really need to have buttons that cannot be used: use SuggestedActions
(see doc here), it will look like the following:
Once clicked the buttons disappear.