UFC 3-240-13FN
25 May 2005
Bottle, with dropper, 50 milliliters (2 ounces) (for phenolphthalein indicator
solution)
Graduated cylinder, 10 milliliters (0.3 ounce)
Casserole, porcelain, heavy duty, 210-milliliter (7.1-ounce) capacity
Stirring rod
Reagents:
Sodium hydroxide solution, 1.0 normality (N)
Phenolphthalein indicator solution, 0.5%
Method:
1. Measure 10 milliliters of acid solution accurately in the graduated cylinder.
2. Pour into the casserole.
3. Add 2 to 4 drops of phenolphthalein indicator solution to the casserole and
stir.
4. Fill the automatic burette with the 1.0 N sodium hydroxide solution; allow
the excess to drain back into the bottle.
5. While stirring the acid solution constantly, add sodium hydroxide solution
from the burette to the casserole until color changes to a permanent faint
pink. This is the endpoint. Read the burette to the nearest 0.1 milliliter
(0.003 ounce).
Results:
1. For hydrochloric acid:
Percent hydrochloric acid = milliliter of 1.0 N sodium hydroxide x 0.36
2. For sulfamic acid:
Percent sulfamic acid
= milliliter of 1.0 N sodium hydroxide x 0.97
193
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