What chemical is commonly used to prevent oxidation in boiler drums and tubes?

Sodium sulfite is a commonly used chemical in boiler systems specifically for its ability to prevent oxidation. In the context of boiler drums and tubes, oxidation can lead to corrosion, which significantly affects the integrity and efficiency of the boiler. Sodium sulfite acts as an oxygen scavenger, reacting with dissolved oxygen in the water to form sodium sulfate. By removing oxygen, it helps to protect metal surfaces from corrosion, thereby prolonging the life of the boiler and maintaining its performance.

The other substances listed, while having various uses in chemical processes or with specific applications in water treatment, do not possess the same effectiveness in preventing oxidation as sodium sulfite does. Sodium carbonate is primarily used to regulate pH levels and soften water, while sodium chloride is often used for different purposes such as brine production. Sodium hydroxide serves as a control agent for pH and can contribute to cleaning, but it does not target oxidation in the same way.