Which of the following anesthetic agent is not painful on intravenous administration?

Ketamine: Sho acting, non barbiturate anaesthetic induces a dissociated state in which the patient is unconcious and does not feel pain. This dissociative anaesthesia provide sedation, amnesia and immobility. Not painful on IV administration Propofol: potent anaesthetic but a weak analgesic . Maximum pain on injection. Etomidate:- Hypnotic agent used to induce anaesthetic but lacks analgesic activity. Usually only used for patient with coronary aery diseases or cardiovascular dysfunction. Methohexital:- Barbiturate derivative, sho acting and has rapid onset of action.