Question

An organic compound, X, will react with an excess of calcium metal to produce a salt with the
empirical formula CaC4H6O4.

What could be the identity of X?
1 ethanoic acid
2 butanedioic acid
3 methylpropanedioic acid

With explanation please!

Answer 1

I'm sure you already took the examination, however for other people who are looking for answers!
Hint: Ca has oxidation state +2