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. TABLE 1. VOLUME AND NORMALITY OF HYDROCHLORIC ACID USED FOR EACH FIZZ <br /> RATING <br /> HCl <br /> Fizz Rating (ml) (Normality) <br /> None 20 0.1 <br /> Slight 40 0.1 <br /> Moderate 40 0.5 <br /> Strong 80 0.5 <br /> T. Add distilled water to make a total volume of 125 ml.. <br /> 8. Boil contents of flask for one minute and cool to slightly above roam <br /> temperature. Cover tightly and cool to room temperature. CAUTION: Do not <br /> place rubber stopper in hot flask as it may implode upon cooling. <br /> 9. Titrate, using 0.1 N NaOH or 0.5 N NaOH (concentration exactly known), to <br /> PH 7.0 using an electrometric pH meter and buret. The concentration of NaOH <br /> used in the titration should correspond to the concentration of the HCl used <br /> in step 5. NOTE: Titrate with NaOH until a constant reading of pH 7.0 <br /> remains for at least 30 seconds. <br /> 10. If less than 3 ml of the NaOH is required to obtain a pH of 7.0, it is <br /> likely that the HCl added was not sufficient to neutralize all of the base <br /> present in the 2.00 g sample. A duplicate sample should be run using the <br /> next higher volume or concentration of acid as indicated in Table 1. <br /> 11. Run a blank for each volume or normality of acid using steps 5,7, 8, <br /> and 9. <br /> 3.2.3.6 Calculations--- <br /> 1. Constant (C) = (ml acid in blank)/(ml base in blank). <br /> 2. ml acid consumed = (ml acid added) - (ml base added X C). <br /> 3. <br /> Tons CaCO3 equivalent/thousand tons of material = (ml of acid consumed) <br /> X (25.0) X (N of acid). <br />_' S0 <br />