56. Solving a chemistry problem

2. To determine the content of phenol in the analyzed water, acid and an excess of potassium bromide were added to a 100 ml sample of water, and coulometric titration of phenol was carried out with electrogenerated bromine at a constant current of 30 mA.
To complete the reaction
It took 8 min 20 s.
Calculate the concentration (µg/l) of phenol in the analyzed water (M = 94.117 g/mol).
How is the titrant obtained in this titration? What generator electrode is used in this case? Write an equation for the corresponding reaction.