All the following are oxidation–reduction reactions except: a. H2(g) + F2(g) → 2HF(g).
b. Ca(s) + H2(g) → CaH2(s).
c. 2K(s) + 2H2O(l) → 2KOH(aq) + H2(g).
d. 6Li(s) + N2(g) → 2Li3N(s).
e. Mg3N2(s) + 6H2O(l) → 3Mg(OH)2(s) + 2NH3(g).

e. Mg₃N₂(s) + 6H₂O(l) → 3Mg(OH)₂(s) + 2NH₃(g)

Explanation:

All the following are oxidation–reduction reactions except:

a. H₂(g) + F₂(g) → 2HF(g).  Redox. H is oxidized and F is reduced.

b. Ca(s) + H₂(g) → CaH₂(s).  Redox. Ca is oxidized and H is reduced.

c. 2K(s) + 2H₂O(l) → 2KOH(aq) + H₂(g).  Redox. K is oxidized and H is reduced.

d. 6Li(s) + N₂(g) → 2Li₃N(s).  Redox. Li is oxidized and N is reduced.

e. Mg₃N₂(s) + 6H₂O(l) → 3Mg(OH)₂(s) + 2NH₃(g). Not redox. All the elements have the same oxidation number

a polar bond is formed when electrons are shared unevenly between atoms

the correct answer would be d. hope this !