Two isomeric alcohols A' and 'B' having composition, C = 60%, H = 13.3%, O = 26.7% possess the vapour density 30. When the vapours are passed separately over heated alumina results in the same product "C", which decolourises the reddish brown colour of bromine solution in CCl_(4). Identify C.

Two isomeric alcohols A' and 'B' having composition, C = 60%, H = 13.3

1.	Two isomeric alcohols A' and 'B' having composition, C = 60%, H = 13.3%, O = 26.7% possess the vapour density 30. When the vapours are passed separately over heated alumina results in the same product "C", which decolourises the reddish brown colour of bromine solution in CCl_(4). Identify C.
Answer» `CH_(3)-CH=CH_(2)` `CH_(3)-overset(CH_(3))overset(\|)C=CH_(3)` `CH_(3)-underset(CH)underset(\|)CH=CH_(2)` `CH_(2)=CH_(2)` Solution :Relative number of atoms of `C = (60)/(12)= 5, H= (13.3)/(1.008)= 13.2, O= (26.7)/(16)= 1.67` Atoms ratio is `C: H: O= (5)/(1.67): (13.2)/(1.67): (1.67)/(1.67)= 3:8:1` Hence empirical formula is `C_(3)H_(8)O`. `implies` Empirical formula mass = 60 As molecular mass `2 xx 30 = 60` So the molecular formula is also `C_(3)H_(8)O`. Hence the two alcohols .A. and .B. are `underset("(Propan-1-ol)")(CH_(3)-CH_(2)-CH_(2)-OH)` and `underset("(Propan-2-ol)")(CH_(3)-underset(OH)underset(\|)CH-CH_(3))` They are DEHYDRATED to propene, when passed over heated alumina. Propene decolourises the reddish BROWN colour of bromine solution. `underset("Propene")(CH_(3)- CH= CH_(2)+ Br_(2)) to CH_(3)- underset(br) underset(\|)CH-underset(br) underset(\|)CH_(2)`