Question 82Steam Plants - Assistant Engineer

The correct answer is A) forms carbonic acid which attacks the watersides. When carbon dioxide (CO2) dissolves in boiler water, it forms carbonic acid (H2CO3). This carbonic acid can be corrosive to the internal surfaces (watersides) of the boiler, potentially leading to pitting and other damage over time. This is why the presence of dissolved CO2 in boiler water is considered dangerous in modern power boilers. The other answer options are incorrect because they do not accurately describe the primary risk posed by dissolved CO2 in boiler water. Options B, C, and D describe different boiler water chemistry issues that are not directly caused by the presence of dissolved CO2.