An organic compound 'X' on heating with conc. `H_(2)SO_(4)` forms a compound 'Y' which on addition of one molecule ofhydrogen in the presence of nickel forms a compound 'Z'. One molecule of compound 'Z' on combustion forms two molecules of `CO_2` and three molecules of `H_(2)O`. Identify, giving reasons the compounds X,Y and Z. write the chemical equations for the reactions involved.

Explanation

Since the compound 'R' (alkane in nature) upon combustino forms two molecules of carbon dioxide and three molecules of water, it is ethane `(C_(2)H_(6))`. The compounds 'P' and 'Q' are ethanol `(C_(2)H_(5)OH)` and ethene `(C_(2)H_(4))` respectively. The chemical reaction are:
`underset("Ethanol (P)")(C_(2)H_(5)OH)underset(heat)overset(H_(2)SO_(4)(Excess))tounderset("Ethene(Q)")(CH_(2))=CH_(2)overset(H_(2)//Ni)tounderset("Ethene (R)")(CH_(3)-CH_(3))`
`underset("Ethene")(C_(2)H_(6)(g))+(7)/(2)(g)overset(heat)to2CO_(2)(g)+3H_(2)O(l)`