Determine the oxidation number for the indicated element in each of the following substances: (d) Br in HBrO
So here we have to figure out the oxidation number in hypobromous acid. Now we know that when hydrogen is connected to non metals, its oxidation number will be +1. When it's connected to metals though or boron, its -1. Oxygen here, we're looking for bromine so this will be X, oxygen here it's not a peroxide or a superoxide so it's going to be -2.
All we've got to do now is solve for the missing variable. So we're going to have one +X plus 1 oxygen which is -2 equals the charge of my molecule which has no charge so it's equal to zero. 1 plus X minus 2 equals zero, X minus 1 equals zero. So the oxidation number here of bromine would have to be +1.