(a) Give chemical tests to distinguish between compounds in the following pairs of substances ,
(i) Ethanal and Propanal
(ii) Benzoic acid and Ethyl benzoate
(b) An organic compound contains `69.77%` carbon , `11.63%` hydrogen and rest oxygen . The molecular mass of the compound is 86. It does not reduce Tollen 's reagent but forms an addition compound with sodium hydrogen sulphite and gives positive iodoform test. On vigorous oxidation, it gives ethanoic and propanoic acids . Derive the structure of the compound.

Answer

(i) For empirical formula
`{:("Element",%, "Relative no. of atoms","Simplest ratio"),(C,69.77,5.76,5),(H,11.63,11.63,10),(O,19.20,1.2,1):}`
`therefore` Empirical formula of compound is `C_(5)H_(10)O`.
and Empirical formula wt. =86
Also Molecular wt. =86
`therefore` Molecular formula of compound is `C_(5)H_(10)O`.
(ii) Compound form bisulphate addition compound and thus, has carbonyl group i.e., aldehyde or ketone.
(iii) It does not reduce Fehling solution and thus, it is not aldehyde but it is ketone.
(iv) It gives positive lodoform test and thus, it has
`(##ALN_CHM_C09(II)_E01_644_A01##)`
`CH_(3).CH_(2).CH_(2)underset(O)underset(||)C.CH_(3)` `(##ALN_CHM_C09(II)_E01_644_A02##)`