Question

Feso 2+0₂ - Fe₂O₃ + S02 oxidation method ​

Answer 1

ANSWER

$2</p><p>FeSO</p><p>4</p><p>→</p><p>Fe</p><p>2</p><p>O</p><p>3</p><p>+</p><p>SO</p><p>2</p><p>+</p><p>SO</p><p>3</p><p>$

Explanation:

Start by identifying the oxidation state for each of the element:

$+</p><p>2</p><p>Fe</p><p>+</p><p>6</p><p>S</p><p>−</p><p>2</p><p>O</p><p>4</p><p>→</p><p>+</p><p>3</p><p>Fe</p><p>2</p><p>−</p><p>2</p><p>O</p><p>3</p><p>+</p><p>+</p><p>4</p><p>S</p><p>−</p><p>2</p><p>O</p><p>2</p><p>+</p><p>+</p><p>6</p><p>S</p><p>−</p><p>2</p><p>O</p><p>3$

- NOT BALANCED

Only three of the four chemicals-

$FeSO</p><p>4</p><p> , </p><p>Fe</p><p>2</p><p>O</p><p>3</p><p> , and \: </p><p>SO</p><p>2$

are directly involved in the redox reaction.

The oxidation state of iron

Fe has increased from

$</p><p>+</p><p>2</p><p> in </p><p>+</p><p>2</p><p>Fe</p><p>+</p><p>6</p><p>S</p><p>−</p><p>2</p><p>O</p><p>4</p><p> \: to \: </p><p>+</p><p>3</p><p> in </p><p>+</p><p>3</p><p>Fe</p><p>2</p><p>−</p><p>2</p><p>O</p><p>3$

by one and therefore Fe is oxidized.

The oxidation state of sulfur S has declined from

$+</p><p>6</p><p> in </p><p>+</p><p>2</p><p>Fe</p><p>+</p><p>6</p><p>S</p><p>−</p><p>2</p><p>O</p><p>4 \: </p><p> \: to \: </p><p>+</p><p>4</p><p> in </p><p>+</p><p>4</p><p>S</p><p>−</p><p>2</p><p>O</p><p>2$

by two and therefore some of the sulfur atoms have been reduced.

The total increases in oxidation numbers shall be the same as the sum of decreases in oxidation numbers in a balanced redox reaction.

The oxidation number increases by 1 for each mole of Fe atom oxidized and decreases by 2

for each mole of S oxidized.

Therefore for each mole of S reduced, two moles of Fe atoms shall be oxidized.

Note that sulfur dioxide,

$+</p><p>4</p><p>S</p><p>−</p><p>2</p><p>O</p><p>2$

, is the only species containing sulfur atoms of oxidation state

+4 . Thus all of the reduced sulfur atoms would end up in

SO2 .

The number of moles of sulfur atoms reduced shall therefore equal to the number of

SO2 molecules produced. This number would be slightly smaller than that of

$+</p><p>2</p><p>Fe</p><p>+</p><p>6</p><p>S</p><p>−</p><p>2</p><p>O</p><p>4$

given that sulfur atoms that were not reduced

got eventually into

$+</p><p>6</p><p>S</p><p>−</p><p>2</p><p>O</p><p>3</p><p>$

Add coefficients 2 and 1 in front of

FeSO4 and

SO2 , respectively:

$</p><p>2</p><p>l</p><p>+</p><p>2</p><p>Fe</p><p>+</p><p>6</p><p>S</p><p>−</p><p>2</p><p>O</p><p>4</p><p>→</p><p>+</p><p>3</p><p>Fe</p><p>2</p><p>−</p><p>2</p><p>O</p><p>3</p><p>+</p><p>1</p><p>l</p><p>+</p><p>4</p><p>S</p><p>−</p><p>2</p><p>O</p><p>2</p><p>+</p><p>+</p><p>6</p><p>S</p><p>−</p><p>2</p><p>O</p><p>3$

−NOT YET BALANCED

Deduce coefficients for the rest of the species based on the conservation of iron and sulfur atoms.

$2</p><p>l</p><p>+</p><p>2</p><p>Fe</p><p>+</p><p>6</p><p>S</p><p>−</p><p>2</p><p>O</p><p>4</p><p>→</p><p>1</p><p>l</p><p>+</p><p>3</p><p>Fe</p><p>2</p><p>−</p><p>2</p><p>O</p><p>3</p><p>+</p><p>1</p><p>l</p><p>+</p><p>4</p><p>S</p><p>−</p><p>2</p><p>O</p><p>2</p><p>+</p><p>1</p><p>l</p><p>+</p><p>6</p><p>S</p><p>−</p><p>2</p><p>O</p><p>3$

BALANCED

Take coefficients "1" out of the expression:

$</p><p>2</p><p>l</p><p>FeSO</p><p>4</p><p>→</p><p>Fe</p><p>2</p><p>O</p><p>3</p><p>+</p><p>SO</p><p>2</p><p>+</p><p>SO</p><p>3</p><p> </p><p></p><p>$