6. Reagents and Materials
6.1 Purity of Reagents - Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society where such specifications are available.
6.2 Purity of Water - For all purposes where water is mentioned, reagent water of a suitable purity shall be used. Various types of reagent water are described in Specification D 1193.
6.3 Acetone (2-propanone), conforming to Specification D 329. (Warning - Extremely flammable. Vapors may cause flashfire.)
6.4 Alcohol, for example, 95 % (V/V) ethanol, or propan-2–ol (isopropyl alcohol), conforming to Specification D 770. (Warning - Flammable.)
6.5 Barium Nitrate, A.R., crystals. (Warning - Barium compounds and their solutions present a health risk if incorrectly handled. Prevent all contact.)
6.6 Hydrochloric Acid, 0.1 mol/L, aqueous. Add 9 mL of A.R. concentrated hydrochloric acid (density 1.19 g/mL) to 1 L with water. (Warning - Corrosive. Causes skin burns.)
6.7 Nitric Acid, 5 mol/L, aqueous. Cautiously add 325 mL of A.R. concentrated nitric acid (density 1.42 g/mL) to 1 L water, while stirring. (Warning - Corrosive. Causes skin burns.)
6.8 Silver Nitrate Solution, standard, c(AgNO3) = 0.1 mol/L, aqueous. Prepare, standardize and store as described in Practice E 200 for 0.1 N aqueous solution, reading concentrations in mol/L in place of normality. Restandardize regularly, but in any case before preparation of the standard 0.01 mol/L solution (see 6.9)
NOTE 1 - Alternatively, ampoules containing concentrated solutions for preparation of standard volumetric solutions are available from various suppliers. (Warning - Silver compounds and their solutions present a health risk if incorrectly handled. Prevent all contact.)
6.9 Silver Nitrate Solution, standard, c(AgNO3) = 0.01 mol/L, aqueous. Prepare shortly before use by accurately diluting one volume of the recently restandardized 0.1 mol/L silver nitrate solution (Warning - see 6.8) to a ten-fold volume with water.
6.10 Sodium Chloride Solution, approximately 1 mmol/L, aqueous. Dissolve 59 6 1 mg sodium chloride in 1 L water.
6.11 Xylene, conforming to Specification D 843. (Warning - Xylene presents a health risk if incorrectly handled. Avoid inhalation. Extract vapor by working in a fume cupboard.)
6.12 Lead Acetate Paper.
6.13 Polishing Paper, 800 grit, or finer, to polish the silver electrode.
