Moles of Na2CO3=massmolar mass
=25.3106
=0.239 moles
Molarity of Na2CO3 solution =number of molesvolume in lire
=0.2390.25(250 ml=0.25 L)
=0.955 M
Now, 1 mole of Na2CO3 contains 2 moles of Na+ and 1 mole of CO2−3 ions.
Therefore,
Concentration of Na+=2×0.955 M=1.91 M
Concentration of CO2−3=1×0.955 M=0.955 M