47.  C : 34,61% : 12 = 2,88    | : 2,88 = 1       | x3 = 3        H : 3,84% : 1 = 3,84       | : 2,88 = 1,33   |x3  = 4        O : 61,55% : 16 = 3,84   | : 2,88 = 1,33   | x3 = 4   C3H4O4 HOOC-CH2- COOH  (C) 48.  C6H5-CH2-CH2-CH3 +5[O] ⇒ C6H5-COOH + CH3-COOH + H2O 2KMnO4 + 3H2SO4 ⇒ K2SO4 + 2MnSO4 + 3H2O + 5[O] nKMnO4 = 474/158 = 3kmoli = 2n C9H12 ⇒  nC9H12 = 1,5kmoli m = 1,5·120 = 180 kg