Soaps do not work in hard water containing calcium and magnesium ions because

Options

A. `Ca^(2+) and Mg^(2+)` ion form insoluble calcium and magnesium salts in the form of scum
B. `Na^(+) and K^(+)` present in soap react with `Ca^(2+) and Mg^(2+)` and hinder cleansing process
C. a large amount of soap is to be used in presence of ` Ca^(2+) and Mg^(2+)`
D. scum formed by combination of `Na^(+),Ca^(2+) and Mg^(2+)` stick to the cloth and are not removed on agitations.

Answer

A

Explanation

`Ca^(+) and Mg^(2+)` ions from insoluble calcium and magnesium soaps respectively when sodium or potassium soaps are dissolved in hard water .
`underset("Soap")(2C_(17)H_35)COONa+CaCl_(2) to underset(" Insoluble calcium stearate (soap)")(2NaCl+(C_(17)H_(35)COO)_(2)Ca)`
These insoluble soaps separate as scum in water and are useless as cleansing agent .