4? I don't know man, this made my brain hurt.
Answer:
NaHCO 3 ( s ) + HC 2 H 3 O 2 ( aq ) ⟶NaHC2H3O2 + H2CO3 → H2O + CO2
NaHCO3 + HC2H3O2 → NaC2H3O2 + H2O + CO2
Explanation:
Sodium bicarbonate and acetic acid reacts to form Sodium acetate and carbonic acid. The carbonic acid then produce carbon dioxide gas and water after undergoing decomposition.
I would guess 36 since the atomic mass of carbon is 12.
Then it would become: S2-
Its charge will be -2.