Total hardness (TH), anion-cation balance

Data:

A sample of water has the following concentrations of ions:

Cation mg/L Anions mg/L

Ca^(2+) 40 SO4^(2-) 67.2

Mg^(2+) 10 HCO3^- 110

Na^+ ? Cl^- 11

K^+ 6



Problem:

Assuming no other constituents are missing, use an anion-cation balance
to estimate the concentration of Na^+

What is the total hardness (TH)?

Draw an ion concentration bar graph