Answer:
SO₄²⁻ (+6)
H₂S (-2)
Step-by-step explanation:
To determine the oxidation number of sulfur in a compound, we need to consider that the sum of the oxidation numbers of the elements present is equal to the charge of the compound.
Some bacteria can extract the oxygen in sulfate ions...
SO₄²⁻
1 × ON(S) + 4 × ON(O) = 2-
1 × ON(S) + 4 × -2 = 2-
ON(S): +6
...reducing the sulfur in them to hydrogen sulfide gas...
H₂S
2 × ON(H) + 1 × ON(S) = 0
2 × +1 + 1 × ON(S) = 0
ON(S): -2