If washing soda is added to hard water, what is the main benefit of insoluble substance formation?
Answer and explanation
Correct answer: Calcium and magnesium ions are removed
The governing concept is the removal of hardness by precipitation. Hard water contains dissolved calcium and magnesium ions. Washing soda, sodium carbonate, supplies carbonate ions that react with these ions and form insoluble calcium carbonate and magnesium carbonate. The precipitates can then be separated, reducing hardness. Thus option A is correct. Sodium ions are not destroyed, and the process neither makes water acidic nor produces chlorine.
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What is the correct answer to this question?
Calcium and magnesium ions are removed
Why is this the correct answer?
The governing concept is the removal of hardness by precipitation. Hard water contains dissolved calcium and magnesium ions. Washing soda, sodium carbonate, supplies carbonate ions that react with these ions and form insoluble calcium carbonate and magnesium carbonate. The precipitates can then be separated, reducing hardness. Thus option A is correct. Sodium ions are not destroyed, and the process neither makes water acidic nor produces chlorine.
Which subject and chapter does this question cover?
This is a Class 10 Science question. Chapter: Chemical Substances – Nature and Behaviour. Topic: Acids, Bases, and Salts.
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