Pinacol Rearrangement.

Explanation

Completely substituted 1,2-diols such as 2, 3-dimethyl-2, 3-butanediol, are known as pinacols. They undergo dehydration and rearrangement in acid to form ketones.
This reaction is called pinacol rearrangement, e.g.
`underset("Pinacal")(CH_(3)-underset(OH)underset(|)overset(CH_(3))overset(|)(C)-underset(OH)underset(|)overset(CH_(3))overset(|)(C)-CH_(3))overset(H^(+))(to)CH_(3)-underset("Pinacolone")(underset(O)underset(||)(C)-underset(CH_(3))underset(|)overset(CH_(3))overset(|)(C)-CH_(3))+H_(2)O`