InterviewSolution
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InterviewSolution
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Permanent hardness due to `Mg^(2+)` ions is best removed byA. `Ca(OH)_(2)`B. `Na_(2)CO_(3)`C. `Na_(2)CO_(3)+Ca(OH)_(2)`D. None of these. |
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Answer» Correct Answer - C `Ca(OH)_(2)` removes the permanent hardness due to `Mg^(2+)`ion, but it produces `Ca^(2+)` ions which are removed by `Na_(2)CO_(3)`. `Mg^(2+)+Ca(OH)_(2)toMg(OH)_(2)darr+Ca^(2+)` `Ca^(2+)+Na_(2)CO_(3)toCaCO_(3)darr+2Na^(+)` `Ca(OH)_(2) or Na_(2)CO_(3)` alone cannot remove the permanent hardness due to `Mg^(2+)` effectively. |
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