Which of the following salts cause least hardness to water when converted to CaCO3CaCO_3CaCO3 equivalents?
10 mg of CaCO3CaCO_3CaCO3
19 mg of CaSO4CaSO_4CaSO4
10 mg of MgCl2MgCl_2MgCl2
10 mg of CaCl2CaCl_2CaCl2
(B) 19 mg of CaSO4CaSO_4CaSO4
Explanation: