By adding which of the following process, permanent hardness of water can be removed.

Options

A. Sodalime
B. Sodiumbicarbonate
C. Washing soda
D. Sodium chloride

Answer

C

Explanation

Washing soda removes both the temporary and permanent hardness by converting soluble calcium and magnesium compounds into insoluble carbonates.
`CaCl_2 + Na_2CO_3 rarrCaCO_3 + 2NaCl`
`CaSO_4 + Na_2CO_3 rarr CaCO_3 + Na_2SO_4`
`Ca(HCO_3)_2 + Na_2CO_3 rarr CaCO_3 + 2NaHCO_3`