A compound C , reacts with Na- metal to form a compound R and evolves a gas

A compound C , reacts with Na- metal to form a compound R and evolves a gas which bums with a pop sound. Compound C on treatment with an alcohol A in presence of an acid forms a sweet smelling compound S . On addition of NaOH to C, it also gives R and water. S on treatment with NaOH solution gives back R and A.
Identify C, R, A, S and write down the reactions involved.

C — Ethanoic acid.
R — Sodium salt of ethanoic acid (sodium acetate) and gas evolved is hydrogen.
A — Methanol.
S — Ester (Methyl acetete).