Which of the following compounds is known to act as a hypnotic?

Step-by-step solution

Paraldehyde is a cyclic trimer of acetaldehyde, formed when acetaldehyde is treated with a few drops of concentrated sulphuric acid at room temperature. It is a central nervous system depressant and is used in medicine as a hypnotic (sleep-inducing agent) and sedative. Metaldehyde is a cyclic tetramer of acetaldehyde used as a molluscicide, while acetaldehyde itself does not act as a hypnotic. Answer: Paraldehyde