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The concentration of fluoride, lead, nitrate, and iron in a water sample from an underground lake was found to be 1 ppm, 40 ppm, 100 ppm and 0.2 ppm, respectively.  This water is unsuitable for drinking due to high concentration of :  
Option: 1 Fluoride
Option: 10  Lead
Option: 19 Nitrate
Option: 36 Iron

Answers (1)


As we learned in concept

Hard Water -

It contains calcium and Magnesium salt in the form of hydrogen carbonate , chloride and sulphate

- wherein

Hard water does not give Lathers with soap.


Maximum permissible concentration of constituents

lead : 50 ppm

nitrate : 50 ppm

Iron : 0.2 ppm

fluoride: 1 ppm


Therefore, option (3) is correct.

Posted by

Ritika Jonwal

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