High school chemical redox reaction

That is, 3BrF3+5H20=9HF+HBrO3+O2↑+Br2, in which the valence of only two O atoms changed from -2 to 0 (that is, the number of O atoms oxidized was 2), all of which came from H2O, that is, two waters were oxidized, and all three BRFs participated in the gain and loss of electrons, but 1 became HBrO. That is, 2 H2O and 1 BrF3 decrease 2 BrF3. According to the gain and loss of electrons (O is 4 electrons and Br is 2 electrons), it is known that 2 H2O reduces 4/3 BrF3, so 0.3mol of water is oxidized and 0.2molBrF3 BRF3 is reduced, with 27.4g g.