# What is the oxidation number of sulfur in an HSO4- ion?

Oct 26, 2015

${S}^{\text{+6}}$

#### Explanation:

Some knowledge in oxidation numbers and algebra is in order.

For H atom, the most common oxidation state is +1.
For O atom, the most common oxidation state is -2.

Substituting $H S {O}_{4}^{-}$ with its oxidation state values we have:

$\left(+ 1\right) + x + \left[\left(- 2\right) \cdot \left(4\right)\right] = - 1$, where $x$ = unknown

$\left(+ 1\right) + x + \left(- 8\right) = - 1$

$x + \left(- 7\right) = - 1$

$x = - 1 + \left(+ 7\right)$

$x = + 6$

Therefore, the correct answer is ${S}^{\text{+6}}$