The amount of charge in F (Faraday) required to obtain one mole of iron from $$Fe_3O_4$$ is ______. (Round off to the nearest integer)

In $$\mathrm{Fe_3O_4}$$, the oxidation state of oxygen is:

$$\mathrm{O = -2}$$

Let the average oxidation state of iron be $$\mathrm{x}$$.

For a neutral compound:

$$\mathrm{3x + 4(-2) = 0}$$

$$\mathrm{3x - 8 = 0}$$

$$\mathrm{3x = 8}$$

$$\mathrm{x = +\frac{8}{3}}$$

Thus, iron is reduced from $$\mathrm{+\frac{8}{3}}$$ to $$\mathrm{0}$$.

For one mole of $$\mathrm{Fe_3O_4}$$:

$$\mathrm{3\ Fe^{+\frac{8}{3}} \longrightarrow 3\ Fe^0}$$

Total electrons required:

$$\mathrm{3\times\frac{8}{3} = 8\ mol\ e^-}$$

Since:

$$\mathrm{1\ mol\ e^- = 1\ F}$$

Charge required for producing $$\mathrm{3\ mol}$$ of iron:

$$\mathrm{= 8\ F}$$

Therefore, charge required for producing $$\mathrm{1\ mol}$$ of iron:

$$\mathrm{= \frac{8}{3}\ F}$$

$$\mathrm{= 2.667\ F}$$

Rounding to nearest integer:

$$\boxed{\mathrm{3}}$$