Question

7,4 g acid monocarboxilic saturat, A, reactoneaza cu 100 cm3 solutie de NaOH de concentratie 1 M. Se cere:
a.Determina dolmula moleculara a acidului carboxilic A
b.Scri ecuatiile reactiilor chimice date de acidul A cu Fe si Al(OH)3
c.Scrie forluma de structura a omologului inferior al acidului A

Answer 1

a)
Notam acidul: R-COOH;
Cm=n/Vs => n=C*Vs=1*0,1=0,1moli
R + 45.......1mol
R-COOH + NaOH -> R-COONa + H2O
7,4g...........0,1moli
R+45=(7,4/0,1)=74 => R=29
M CnH2n+1=14n+1=29 => 14n=28 => n=2
formula moleculara: C3H6O2
formula de structura: CH3-CH2-COOH
b)
2CH3-CH2-COOH + Fe -> (CH3-CH2-COO)2Fe + H2
3CH3-CH2-COOH + 2Al(OH)3 -> (CH3-COO)3Al + 3H2O
c)
omologul inferior: CH3-COOH