Permanent hardness is due to `CI^(ɵ)` and `SO_4^(2-)` of `Mg^(2+)` and `Ca^(2+)` and is removed by adding `Na_2CO_3`.
`{:(CaSO_(4)+Na_(2)CO_(3)toCaCO_(3)+Na_(2)SO_(4)),(CaCl_(2)+Na_(2)CO_(3)toCaCO_(3)+2NaCl):}` Which of the following statements is`//`are correct?
A. If hardness is 100PPm `CaCO_(3)` the amount of `Na_(2)CO_(3)` required to soften 10L of hard water is 10.6h
B. If hardness is 100PPm, `CaCO_(3)` ,the amout of `Na_(2)CO_(3)` required to soften is 10l of hard water is 10.6g
C. If hardness id 420 ppm `MgCO_(3)` the amout of `Na_(@)CO_(3)` required to soften 10L of hard water is 5.3h
D. If hardness id 420 ppm `MgCO_(3)` the amout of `Na_(@)CO_(3)` required to soften 10L of hard water is 53.0g
