mA = 40·0,54 = 21,6g (R-CH=O)
mB = 72·0,1 = 7,2g
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ms = 112 g ......................21,6gA ..........................7,2gB
56 g....................x = 10,8 g A.......................3,6g B
R-CH=O +2 [Ag(NH3)2]OH ⇒ R-COOH +2 Ag↓+ 4NH3 + H2O
nAg = 2nA 25,92/108 = 2·10,8/M M = 90g/mol
A : CxH2xOy 14x + 16y = 90 y ≥ 2
ptr. y = 2 14x = 58 x ∉N
y = 3 14x = 42 x = 3 C3H6O3 HO-CH2-CH(OH)-CH=O