Analisis asam boraks dg alat potensiometer, titrino / Titroprocessor

Alat yg digunakan
Potentiometer = 751 GPD Titrino / Titroprocessor
Electrodes = 6.0232.100 combined pH glass electrode; input 1

Pereaksi
c(NaOH) = 0.1 mol/L; D0

Sample
5.00 mL c(H3BO3) = 0.1 mol/L
10 mL d-mannitol solution, saturated
40 mL dist. Water

Remarks

· Determination reaction:
Boric acid forms an ester with mannitol:
HO-CH HC-O O-CH -
H3BO3 + 2 → B H+ + 3 H2O
HO-CH HC-O O-CH

H3BO3+2H4C2O2 →( H4C4BO4 ) - H ++ 3 H2O

· Calculations:

Bor=EP1*C01*C02*C37/C00;1;mg/l

Bor = content of Bor in mg/L
C01 = bor equivalent (1.081 mg/mL titrating agent)
C02 = factor for the conversion mL Þ L (1000)
C37 = titer of titrating agent (1.0013)
· d-mannitol solution, saturated:
App. 200 g d-mannitol dissolved in dist. water.

. Answer

Bor = 4.719 x 1.081 x 1000 x 1.0013 / 5.0 = 1021.6 mg/L

EP1 = 4.719 mL
C00 = 5.0 mL

Literature
· Metrohm Application Bulletin No. 66: Potentiometric
determination of boric acid.