Problem page write a balanced half-reaction describing the oxidation of aqueous chromium (ii) cations to aqueous chromium (iv) cations.

The balanced half-reaction: Cr²⁺⁺ (aq) → Cr⁴⁺ (aq) + 2e⁻.

Chromium (II) cations two electrons and became chromium (IV) cations.

Oxidation reaction is increasing of oxidation number of element, because element or ion lost electrons in chemical reaction.

Reduction is lowering oxidation number because element or ions gain electrons.