The chemical equation, Cr + Fe(NO3)2 → Fe + Cr(NO3)3, is an example of which type of reaction?

Redox type

Explanation:

The reaction is:

2Cr +  3Fe(NO₃)₂ → 2Fe + 2Cr(NO₃)₃

2 moles of chromium can react to 3 moles of iron (II) nitrate in order to produce 2 moles of iron and 2 moles of chromium nitrate.

If we see oxidation state, we see that chromium changes from 0 to +3

Iron changed the oxidation state from +2 to 0

Remember that elements at ground state has 0, as oxidation state.

Iron is being reduced while chromium is oxidized. Then, the half reactions are:

Fe²⁺  +  2e⁻ ⇄  Fe    (Reduction)

Cr ⇄ Cr³⁺  +  3e⁻    (Oxidation)

When an element is being  reduced, while another is being oxidized, we are in prescence of a redox reaction.