Answer:
The compound Z must be ethanoic acid.
Step-by-step explanation:
It is clear from the options that the reaction is of an acid with calcium metal. The first acid given is monoprotic so one mole of calcium will react with two moles of acid to give calcium salt of diacid.
As per the given formula of the salt produced there are four carbons in the compound with one calcium so there must be two carbons in the acid with which calcium was reacted Or if the acid reacted is diprotic acid then there must be four carbon in it.
The molecular formulae of given acids are:
a) ethanoic acid: CH₃COOH [two carbons and it will form Ca(CH₃COO)2 or CaC₄H₆O₄.
b) butanedioic acid: C₄H₆O₄
If it will react with calcium it will form CaC₄H₄O₄: so it cannot be the compound "Z".
c) methylpropanedioic acid: C₄H₆O₄
If it will react with calcium it will form CaC₄H₄O₄: so it cannot be the compound "Z".
The structure are also shown in the figure.