🔍 Key Concepts

• Boiler water treatment goals – preventing scale, corrosion, and carryover • Phosphate treatment – how it reacts with hardness ions like calcium and magnesium • Difference between removing oxygen, controlling alkalinity, and dealing with scale-forming salts

💭 Think About

• Ask yourself: what specific boiler water problem do calcium and magnesium hardness cause, and how do phosphates interact with those ions? • Which of the choices specifically talks about changing the form of scale-forming materials rather than removing gases like oxygen? • Think about which boiler problems are handled by other chemicals (like oxygen scavengers or pH/alkalinity adjusters), and eliminate those options.

✅ Before You Answer

• Identify which answer choice refers to scale or hardness rather than gases or metal embrittlement • Confirm that dissolved oxygen is normally treated with chemicals like sulfites, not phosphates • Remember that hydrogen embrittlement and vanadium control are usually associated with fuel/metal issues, not basic boiler water phosphate treatment