The books published by the Teaching and Research Section of Basic Education in Henan Province are the authoritative materials for our college entrance examination in Henan Province. I dare not change the answer in it at will. Last year, I thought the answer to one question was not accurate enough, so I corrected it for my classmates in private. As a result, the joint exam just came out. The answer is exactly the same as the information. I blamed myself for a long time, feeling sorry for the students and afraid to tell the leaders, but last year, this year, I was still troubled by a problem. On page 72 of chemical description and detection, there is still such a problem. After 2 grams of potassium permanganate is completely decomposed, it should be able to generate 0.203 grams of oxygen through theoretical calculation, but in fact it has collected 0.253 grams, which is larger than the theoretical value. Then why? The answer is: Supertheoretical oxygen may come from oxygen. I have been studying this problem, but I just can't understand the answer. According to this idea, the oxygen in the air can only be the original air in the test tube containing potassium permanganate, but according to that idea, the device in that question will also leave an oxygen test tube, so I don't think this answer is appropriate. I agree with the answer that hypertheoretical oxygen may come from the decomposition of potassium permanganate into oxygen, which shows that testing is the authoritative counseling material for our senior high school entrance examination. I still dare not change the answers for the students, so it is very contradictory. I hope my colleagues who teach chemistry in Henan can talk about their own views!