The oxide of titanium, TiO2 is used as a "whitener" in toothpaste. It is obtained from the ore iron (II) titanate, FeTiO3. What is the change, if any, in the oxidation number (oxidation state) of titanium in the reaction

There is no change in the oxidation number (oxidation state) of titanium in the reaction

Explanation:

TiO2

⇒ The oxidation number of O = - 2

⇒ Since we have O2, this makes 2*-2 = - 4

⇒ The oxation number of Ti and O2 together should be 0

⇒The oxidation number of Ti is + 4

For FeTiO3, it's more complicate because Fe can have several oxidation numbers.

Since FeTiO3 has three short metal-oxygen bonds in the octahedron and three long metal - oxygen bonds.

The valences, obtained from the bond lengths by the bond valence method, is + 2 anapproximately which can be rounded off to oxidation stated + 4, respectively for Fe and Ti.

FeTiO3

⇒ The oxidation number of O = - 2

⇒ We have O3 so this makes 3*-2 = - 6

⇒Fe has an oxidation state of + 2

⇒The oxidation state of Fe, Ti and O3 together should be 0

⇒Ti has an oxidation state of + 4

This means Titanium doesn't change it's oxidation number.

There is no change in the oxidation number (oxidation state) of titanium in the reaction