Ion-Exchange Resins Can Remove Mg²⁺ and Ca²⁺ in Water (Called

Ion-exchange resins can remove Mg²⁺ and Ca²⁺ in water (called softening) by releasing Na⁺. What would be the concentration of sodium ion in the softened water if the combined concentration of these Group 2A ions that were removed from the hard water was 0.026 M?

A) 0.052 M
B) 0.26 M
C) 0.13 M
D) 0.00 M
E) Can't tell, necessary information is lacking.