Question 389Steam Plants - Assistant Engineer70% to pass
A sample of boiler water can be chemically tested for alkalinity by initially adding a few drops of phenolphthalein and then slowly titrating the water sample until the _______________.
AI Explanation
The correct answer is B) the sample color changes from pink to clear.
Explanation:
To test the alkalinity of a boiler water sample, phenolphthalein is added initially. Phenolphthalein is a pH indicator that turns pink in alkaline solutions. The sample is then slowly titrated (added drop by drop) with an acid until the pink color disappears and the solution becomes clear. This point indicates that the alkalinity has been neutralized, and the alkalinity of the sample can be determined.
The other options are incorrect because: A) the sample does not change from clear to pink, it changes from pink to clear; C) the chloride concentration is not being measured, only the alkalinity; and D) the titration is continued until the pH reaches the endpoint, not a specific pH of 10.5.
Related Questions
#387 A dissolved oxygen concentration of 8.0 ppm represents _______________.#388 Normally a boiler water sample should be taken _______________.#390 What boiler water chemistry is necessary to ensure the precipitation of hard scale forming calcium? #391 A boiler water sample being collected for analysis should be circulated through a cooling coil because _______________.#392 A boiler with a water capacity of 10 tons generates steam at the rate of 30 tons per hour. If the feed water quality is 0.5 ppm, the concentration of solids will increase 1.5 ppm every hour. What would be the increase in the concentration of solids within 24 hours?