a hydrocarbon A of molecular weight 54 reacts with excess of BBr2 in CCl4 to give the compound B whose molecular weight 493% more than that of A . how ever on hydrogenation with excess of Hydrogen , A form C whose molecular weight is just 7.4% more than A . A reacts with CH3CH2Br in presence of NaNH2 to give another Hydrocarbon D which on ozonolysis yields diketonbe E , E on oxidation gives propanoic acid . give all reaction and structures of ABCDE and reasons too