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(e)

Repeat in triplicate.

170

(f)

Calculate concentration of the silver nitrate solution according to section

I

a. The difference

171

between the calculated concentration and the certified value should be within 0.5%. If outside the

172

acceptance value, check the experimental procedures and titration system. If issue is not

173

resolved, then use fresh standardized silver nitrate. If fresh standardized silver nitrate does not

174

provide an acceptable result, replace the electrolyte of the electrode and check the operating

175

condition of the dosing unit.

176

177

178

I. Calculations

179

(a)

Calculate silver nitrate concentration (SNC) in mol/L for system suitability verification and

180

report to 4 decimal places:

181

182

If using

[

D

b

]

183

10 V

5.844

) /

(

1

1

u u

m

L mol

SNC

184

185

Where

186

݉

1

= weight of sodium chloride in 5 mL or 1 mL of [Db] standard solution (mg);

187

ܸ

1

= Volume of 0.1 M or 0.02 M AgNO

3

consumed at titration endpoint (mL);

188

5.844 = sodium chloride weight in μg corresponding to 1 mL of 0.1 mol/L

AgNO

3

;

189

10 = mass conversion from titer to the concentration of titrant.

190

191

Or if using purchased standard grade 0.10 M NaCl

[

C

h]

192

1

3

V

1.0 ) /

(

V

L mol

SNC

u

193

194

Where

195

͵

= volume of purchased standard grade 0.10 M sodium chloride added (mL);

196

ܸ

1

= Volume of 0.1 M or 0.02 M AgNO

3

consumed at titration endpoint (mL);

197

198

199

200

201

(b

)

Calculate chloride content in sample (CL) and report to 3 significant digits:

202

203

m

100

)

( c 45.35 ) 100 /

(

0 -2

uu

uu

f

VV

g mg CL

204

W

here:

205

2015.07/2015.08 (February 2016)

Chlor-02/Chlor-04

FOR ERP USE ONLY

DO NOT DISTRIBUTE