Question 146Steam Plants - 1st Asst/Chief
70% to passA 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 _______________.
Asample color changes from pink to clear
Bwater sample pH reaches 10.5
Centire concentration of chlorides have been neutralized
Dsample color changes from clear to pink
AI Explanation
The correct answer is A) the sample color changes from pink to clear. The reasoning is that phenolphthalein is a pH indicator that turns pink in alkaline solutions. When titrating a boiler water sample with an acid solution, the sample's alkalinity is neutralized, causing the pink color to disappear as the pH drops below 8.2, the phenolphthalein endpoint. The other options are incorrect because B) reaching a pH of 10.5 is not the endpoint for alkalinity testing, C) chlorides are not being neutralized in this test, and D) the color change should be from pink to clear, not clear to pink.
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