Penentuan secara Potentiometric of Pure Silver Content

Peralatan
Potentiometer = 751 GPD Titrino / Titroprocessor
Electrodes = 6.0404.100 combined massive Ag electrode with AgBr coating; input 1

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

Sample
app. 250 mg Ag
10 mL HNO3 65 %
100 mL dist. water

Remarks
Calculations:

Silver=EP1*C01*C02*C03*C04/C00;3;%

Silver = content of silver in % ( purity )
C01 = concentration of titrating agent (0.1 mol/L)
C02 = titer (1.0)
C03 = molecular mass of Ag (107.87 g/mol)
C04 = factor for % (100)

Answer

Silver = 22.332 x 0.1 x 1.0 x 107.87 x 100 / 257.7 =93.479 %

EP1 = 22.332 mL
C00 = 257.7 mg

Sample preparation:
Heat silver in HNO3. Allow nitrous fumes to evaporate.

AgBr coating of electrode:
Clean Ag electrode with scouring agent and electrolyse in (HBr) = 0.1 (10%) during 2 h with 5 mA using a 6.0305.000 Pt lectrode as cathode. Stir during electrolysis.

Literature
Metrohm Application Bulletin No. 61: Potentiometric determination of silver.