🔍 Key Concepts

• Scale formation in boilers and how dissolved minerals behave when heated • Difference between precipitation (forming removable sludge) and dissolution (staying in solution) • Effect of boiler water pH (acidity/alkalinity) on corrosion and scale

💭 Think About

• Ask yourself: In a real boiler, what kind of by‑product can be more easily removed by blowing down the boiler – hard scale on the metal or soft sludge in the water? • Think about which choice describes a process that changes the form of scale‑forming salts so they are less likely to stick to heating surfaces. • Consider which options would increase corrosion risk instead of helping boiler operation, and rule those out first.

✅ Before You Answer

• Identify which option talks about turning dissolved salts into a form that can be removed with blowdown. • Eliminate any option that would clearly raise corrosion, such as making the water more acidic. • Focus on the answer that best matches standard boiler practice: keeping heating surfaces clean by converting potential scale into easily removable material.