Question

Lime and soda are added to water to remove:

• A. {Pathogens}
• B. {Iron}
• C. {Hardness}
• D. {Nitrates}

Hint:

The lime-soda process effectively removes hardness by precipitating calcium and magnesium ions.

Answer 1

The Correct Option is C

Step 1: The lime-soda process is used for softening hard water by removing calcium and magnesium ions. \[ {Ca}^{2+} + {Lime/Soda} \rightarrow {CaCO}_3 \downarrow \] \[ {Mg}^{2+} + {Lime} \rightarrow {Mg(OH)}_2 \downarrow \] Step 2: This process does not remove pathogens, iron, or nitrates. Thus, the correct answer is (C) Hardness.