Determine the oxidation state of elements in the following compounds: CBr4 KBrO3 HClO4.

CBr4 – bromine has an almost constant degree of oxidation (-1), which means that carbon must have such an oxidation state to balance the four bromine ions. In total, bromine will have a charge (-4), so carbon has an oxidation state (+4);
КBrO3- oxygen has a constant oxidation state (-2), potassium (+1). There are 3 oxygen ions in the same compound, which means (-6) + (+ 1) = (- 5) the total number that bromine must balance. This means that bromine has an oxidation state (+5);
HClO4- at oxygen s.d. is equal to (-2). There are 4 oxygen ions, which means 4 × (-2) = – 8. Hydrogen has a constant s.r. equal to (+1). The total number to balance for bromine is (-8) + (+ 1) = (- 7). Hence, s.o. bromine (+7).