So in our chem trial, there was a question on Industrial chem which asked for an environmental issue of the Frasch Process. I wrote "sulfur can oxidise or reduce at the surface producing SO2 or H2S. Now the teachers are saying that they are not accepting this answer. I have shown them several textbooks as well as the Board of Studies sample answers, but they are still not accepting it. I have one more thing that I hope will work: the powepoint presentation showed to us by the teachers, stating that this is one of the environmental issues. Because if the teachers show that to us, we can assume that it is right??? Am I right?