Final answer:
The correct IUPAC names are chromium(VI) bromate for Cr(BrO)3, octaiododiselenium for Se2I8, and barium hydrogen phosphate for BaHPO4.
Step-by-step explanation:
The correct IUPAC name for Cr(BrO)3 is chromium(VI) bromate. In this name, 'chromium' refers to the metal ion Cr, and '(VI)' indicates the oxidation state of chromium is +6. 'Bromate' is the name of the polyatomic ion BrO3-, with a -1 charge on each ion.
The correct IUPAC name for Se2I8 is octaiododiselenium. This name describes that there are two selenium (Se) atoms and eight iodine (I) atoms in the compound.
For BaHPO4, the correct IUPAC name is barium hydrogen phosphate. 'Barium' represents the Ba2+ cation, and 'hydrogen phosphate' is the polyatomic ion HPO42-.