In the conversion of Br₂ to BrO₃⁻, the oxidation number of Br changes from

Options

(a) zero to 5
(b) 1 to 5
(c) zero to -3
(d) 2 to 5

Correct Answer:

zero to 5

Explanation:

Br → BrO₃⁻
Any free (unattached)element with no charge has the oxidation state of zero.
Let the Oxidation number of Br in BrO₃⁻ be x.
Hence x + 3(-2) = -1, x – 6 = -1, x -6 + 5 = -1, x = +5.