An acidic compound `(A) (C_4 H_8 O_3)` loses its optical activity on strong heating yielding `(B) (C_4 H_6 O_2)` which reacts readly with `KMnO_4`. `(B)` forms a dervative `( C)` with `SOCl_2` which on reaction with `(CH_3)_2 NH` gives `(D)`. The compound `(A)` on oxidation with dilute chromic acid gives an unstable compound `(E)` which decarboxylates readily to give `(F) (C_3 H_6 O)`. The compound `(F)` gives a hydrocarbon `(G)` on treatment with amalgamated `Zn` and `HCl`. Give the structures of `(A)` to `(G)` with proper reasoning.

Explanation

(i) `[A] rArr 1^@` unsaturation, on heating loses `(-H_2 O)` (Hydroxy acid) due to `(-overset(O)overset(||)(C)-OH) `group.
(ii) rArr Third oxygen atom due to `(-OH group)`.
(iii) `A` rArr Optically active. So,
`underset(beta-"Hydroxy")(C-underset(OH)underset(|)(C)-C)-COOH [or] underset(alpha-"Hydroxy")(C-C-underset(OH)underset(|)(C)-COOH)`
(iv) Since `(A)` on heating loses `H_2 O`, thus `(A)` is `beta-`hydroxy not `alpha-`hydroxy. because only `beta-`hydroxy loses `H_2 O` on heating.
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