Explain the action of soap with hard water.

Explanation

(i) The cleaning capacity of soap is reduced when used in hard water.
(ii) Soaps are sodium or potassium salts of long chain fatly acids.
(iii) When soap is added to hard water, the divalent magnesium and calcium cations present in hard water react with soap
(iv) The sodium salts present in soaps are converted to their corresponding magnesium and calcium salts which are precipitated as sum or precipitate.
`M^2+2RCOONato(RCOO)_2M(s)+2Na_((aq))^+`
Where M=Ca or Mg
`R=C_(17)H_(35)`