How can I work out which gas is released when ethanoic acid is reacted with sodium?

Ethanoic acid is CH₃COOH. Acids can ionise, producing H⁺ ions and in this case, CH₃COO (ethanoate) ions. The sodium exists as Na⁺ ions in solution, which then create neutral ion complexes with the ethanoate ions, as CH₃COO Na⁺ . The displaced H⁺ ions from two of these processes combine to form hydrogen gas, H₂ .