Hydrogen fluoride is used in the manufacture of Freons (which destroy ozone in the stratosphere) and in the production of aluminum metal. It is prepared by the reaction CaF2(aq) H2SO4(aq) CaSO4(s) 2 HF(aq) In an industrial process 6.00 kg of CaF2 are treated with an excess of H2SO4 and yield 2.86 kg of HF. Calculate the percent yield of HF.