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Question
Explain by writing a word equation.
Hard water gets softened on mixing with a solution of washing soda.
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Solution
To soften the hard water, a solution of washing soda is added to it. This results in a chemical reaction to form a precipitate of insoluble carbonate salts of calcium and magnesium. As the dissolved salts of calcium and magnesium go out in the form of a precipitate of the carbonate salts, the water is softened. The following equation can be written for this chemical change.
Word equation:
Calcium chloride + Sodium carbonate `→` Calcium carbonate + Sodium chloride
Chemical equation (unbalanced):
CaCl2 + Na2CO3 → CaCO3 + NaCl
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