Concept:An anesthetic is a substance that causes loss of sensation or consciousness. Among simple chlorinated hydrocarbons, chloroform is the compound historically known as an anesthetic.
Explanation:Chloroform, also called trichloromethane, has the molecular formula
CHCl3.
It was once widely used by inhalation to put patients to sleep before surgery.
It acts by depressing the central nervous system, leading to unconsciousness and loss of pain sensation.
Modern medicine avoids it because it may cause heart failure or liver damage.
Still, chloroform is the recognized anesthetic among the given options.
For comparison,
CCl4 (carbon tetrachloride) is mainly a solvent.
CH2Cl2 (dichloromethane) is also used as a solvent, while
CH3Cl (chloromethane) is a refrigerant.
None of these other compounds serves as a general anesthetic.
Therefore, the correct compound is chloroform.
Answer:B.
CHCl3 (chloroform)