When zeolite, which is hydrated sodium aluminium silicate is treated with hard water, the sodium ions are exchanged with which of the following ion(s)?

a.  ${\mathrm{H}}^{+}$ ions

b.  ${\mathrm{Mg}}^{2+}$ ions

c.  ${\mathrm{Ca}}^{2+}$ ions

d.  ${\mathrm{SO}}_{4}^{2-}$ ions

Choose the correct option
1. (a, b)
2. (b, c)
3. (c, d)
4. (a, d)

Hint:  Water hardness is the amount of dissolved calcium and magnesium in the water.

To make hard water soft, the zeolite method is used. Sodium zeolite or sodium aluminosilicate (Na2Al2 Si2O8·xH2O )is used.

It has a unique property of exchanging cations such as Ca2+ and Mg2+ in hard water for the sodium ion.