25.3 g of sodium carbonate,Na2CO3 is dissolved in enough water to make 250 mL of solution. If sodium carbonate dissociates completely, molar concentration of sodium ion,Na+and carbonate ions, CO32-respectively are (Molar mass of Na2 CO3 = 106 mol-1)

Molarity of Na2CO3 solution =25.3×1000106×250=0.955M                     Na2CO3⟶2Na++CO32−Initial conc.         0.955       0             0After dissociation                 2 x 0.955      0.955∴               Na+=2×0.955M=1.910M                    CO32−=0.955M