Bromine is added to cold dilute aqueous solution of NaOH. The mixture is boiled. Which of the following statements is not true?

On acidification the final mixture gives bromine: 5NaBrO + NaBrO3 + 6HCl → 6NaCl + 3Br2 + 3H2O. Thus, during the reaction, bromine is present in four different oxidation states i.e., zero in Br2, +1 in NaBrO, -1 in NaBr, and +5 in NaBrO3. The greatest difference between various oxidation states of bromine is 6 and not 5. On acidification of the final mixture, Br2 is formed and disproportionation of Br2 occurs during the reaction giving BrO⁻, Br⁻ and BrO3⁻ ions. Hence, option A is correct.