The compound used as an anaesthetic is one of the four options given. To answer this question, we need to identify which of the options is commonly used as an anaesthetic.
The correct answer is which is chloroform (CHCl3). Chloroform was used as an anaesthetic in the past but is now largely replaced by safer and more effective anaesthetics.
Therefore, the compound used as an anaesthetic is chloroform (CHCl3).