71. Solving a chemistry problem

7. A. Is it possible to oxidize the arsenite ion to the arsenate ion under standard conditions with potassium dichromate in an acid medium?
B. A 1.2350 g sample containing phenol was dissolved in a 500 cm3 volumetric flask. To 10 cm3 of the resulting solution was added 50.00 cm3 of a 0.0100 N potassium bromate solution with a correction factor of 0.9997 and a potassium bromide solution (in excess). An excess of potassium iodide was then added to the solution. 35.30 cm3 of a 0.0100 N solution of sodium thiosulfate was used for titration of the released iodine with a correction factor of 1.0240. Determine the mass fraction of phenol in the sample.