An aromatic compound A (C_(2)H_(6)O_(2)) liberates hydrogen with metallic sodium. Compound A when heated with anhydrous zinc chloride ultimately gives B (C_(2)H_(4)O) whereas, when heated with conc. Phosphoric acid gives C (C_(4)H_(10)O_(3)). A on oxidation with acidified K_(2)Cr_(2)O_(7) gives compound D (CH_(2)O_(2)). Identify A, B, C and D. Explain the reactions involved.

An aromatic compound A (C_(2)H_(6)O_(2)) liberates hydrogen with metal

1.	An aromatic compound A (C_(2)H_(6)O_(2)) liberates hydrogen with metallic sodium. Compound A when heated with anhydrous zinc chloride ultimately gives B (C_(2)H_(4)O) whereas, when heated with conc. Phosphoric acid gives C (C_(4)H_(10)O_(3)). A on oxidation with acidified K_(2)Cr_(2)O_(7) gives compound D (CH_(2)O_(2)). Identify A, B, C and D. Explain the reactions involved.
Answer» Solution :(i) An organic compound A `(C_(2)H_(6)O_(2))` liberates hydrogen with metallic sodium. `underset("Ethylene glycol compound"(A))underset(CH_(2)OH)overset(CH_(2)OH)\|overset(NA)underset(323K)to underset("MONOSODIUM glycolate")underset(CH_(2)OH)overset(CH_(2)ONa)\|overset(Na)underset(433 K) to underset("disodium glycolate")underset(CH_(3)ONa)overset(CH_(3)ONa)\|+H_(2)uarr` (ii) Compound A when heated with anhydrous zinc chloride ultimately gives B `(C_(2)H_(4)O)`. (iii) Compound A when heated with conc. phosphoric acid gives `C (C_(4)H_(10)O_(3))`. (iv) Compound A on OXIDATION with acidified `K_(2)Cr_(2)O_(7)` gives compound D `(CH_(2)O_(2))`. `underset(CH_(2)OH)overset(CH_(2)OH)\|overset(3(O))underset("acidified " K_(2)Cr_(2)O_(7))to underset("HCOOH formic acid")overset(HCOOH)+ + H_(2)O`