In order to obtain barium in a form that may be put into solution, the natural barytes, containing only pure barium sulfate and infusible matter, is fused with an excess of pure, anhydrous soda ash. Upon analysis of the fusion mass it is found to contain 11.3% barium sulfate, 27.7% sodium sulfate and 20.35% sodium carbonate. The remainder is barium carbonate and infusible matter. Calculate. i. The % conversion of barium sulfate to barium carbonate.