Question 125General Subjects - Assistant Engineer

The correct answer is A) No change in color (remaining at red with a pH of 2.0) and no more venting of carbon dioxide gas. The continued presence of scale in the feed water heater would be indicated by the heated sulfuric acid remaining red in color with a pH of 2.0. This is because the scale, likely composed of calcium or magnesium compounds, would not have been fully dissolved or removed, and the acid would not have become neutralized. Additionally, the lack of carbon dioxide venting would suggest that the scale was not reacting with the acid. The other options are incorrect because a change in color to orange with a pH of 4.0 (option D) would indicate that the acid had been neutralized, signaling the removal of the scale. Options B and C do not provide accurate indications of the continued presence of scale in this scenario.