Chemistry
Answer
Permutit is an artificial zeolite. Chemically, it is hydrated sodium aluminium orthosilicate, having the formula Na2Al2Si2O8.XH2O. For the sake of convenience, let us give it the formula Na2P.
A tall cylinder is loosely filled with lumps of permutit. When hard water containing calcium and magnesium ions percolates through these lumps, exchange of ions takes place. The sodium permutit is slowly changed into calcium and magnesium permutit, and with the removal of calcium and magnesium ions, the water become soft.
When no longer active, the permutit is regenerated by running a concentrated solution of brine over it and removing the calcium chloride formed by repeated washing.
CaP + 2NaCl ⟶ Na2P + CaI2
Related Questions
Why does the hardness of water render it unfit for use in a
(i) boiler
(ii) for washing purposes?
Explain with equation, what is noticed when permanent hard water is treated with
(a) slaked lime
(b) washing soda
Explain, with equations, why ordinary soap does not lather easily in hard water.
Explain:
(a) The use of lead pipes for drinking water supply is being discontinued.
(b) Chalk hills dissolve in rain water.
(c) Hard water is unfit for boilers.
(d) Iron chloride forms a saturated solution when exposed to the atmosphere.
(e) A bottle containing concentrated H2SO4 should be stoppered.