The reaction of wcl6 with al at 400 degre celius gives blck crystals of a compound contaning only tungsten and chlorine. a sample of this compound , whn reduced with hydrogen chloride, which is absorbed in water. titration of the hydrochloric acid thus produced requires 46.2 ml of 0.1051 m naoh to reach the end point. what is the empirical formula of the black tungsten chloride?