The correct option is B Benzoyl chloride To the specific amounts of cold and dry benzaldehyde are added to the flask and saturated with the current of dry chlorine. The chlorine gas is readily absorbed and the evolution hydrogen chloride takes place. When the reaction has moderated, the external heat is applied by keeping gentle boiling. The stream of chlorine is continued until no more hydrogen chloride is evolved. A stream of dry air or carbon dioxide is then passed through the apparatus in order to remove an excess of chlorine. Benzoyl chloride is obtained by distillation as a colorless fuming liquid with a very irritating smell. Yield almost quantitative.