Compound (A) `(C_(6)H_(12)O_(2))` on reduction with `LiAIH_(4)` yielded two compound (B) and (C). The compound (B) on oxidation gave (D). 2 moles of (D) on treatment with alkali (aqueous) and subsequent heating furnished (E). The later on catalytic hydrogenation gave (C). The compound (D) was oxidized further to give (F) which was found to be monobasic acid (m.wt. 60.0). Deduce structres of (A) to (F)`

Explanation

(i) The compound [F] being a monobasic acid may be represented as RCOOH. As the molar mass of acid [F] is 60, the alkyl group [R] must be methyl group `(-CH_(3))`. This is calculated by subtracting the mass of -COOH group (45) from that of the acid i.e. 60-45=15 and this is the mass due to `CH_(3)` group. Thus, [F] is `CH_(3)COOH`.
(ii) Since the compound [F] is obtained by the oxidation of [D] the compound [D] must be aldehyde i.e. `CH_(3)CHO`.
(iii) The compound [D] was obtained by the oxidation of [B] which must be an alcohol with structure `CH_(3)CH_(2)OH`.
(iv) The compound [D] on treatment with alkali gave alcohol which when heated produced [E] as follows :
`underset("Ethanal"[D])underset()underset()(2CH_(3)CHO)overset(KOH(aq.))rarrunderset("2-Hydroxybutanal")underset()(CH_(3)underset(OH)underset(|)CHCH_(2)CHO)overset("heat")underset(-H_(2)O)rarrunderset("But-2-enal[E]")underset()underset()(CH_(3)CH=CHCHO)`
(v) The compound [E] on acatalytic hydrogenation give [C], `underset([E])underset()(CH_(3)CH=CHCHO)overset(H_(2)//Ni)rarrunderset("Butan-1-01[C]")underset()(CH_(3)CH_(2)CH_(2)CH_(2)OH)`
(vi) Since the compound [A] when reduced with `LiAIH_(4)` gave the compound [B] and [C], it must be an ester i.e. ethylbutanoate.
`underset("Ethylbutanoate [A]")underset()underset((C_(6)H_(12)O_(2)))underset()(CH_(3)CH_(2)CH_(2)COOCH_(2)CH_(3))overset(LiAIH_(4))rarrunderset("Butan-1-01[C]")underset()(CH_(3)CH_(2)CH_(2)CH_(2)OH)+underset("Ethanol [B]")underset()(CH_(3)CH_(2)OH)`