JAMB - Chemistry (1980 - No. 45)
Detergents are more advantageous than soaps in hard water districts because
on treatment with hard water they either form soluble calcium salts or do not react with calcium ion
on treatment with hard water they form soluble calcium salts
on treatment with hard water they form sodium salts
on treatment with hard water they are converted into soaps
on treatment with hard water they form more lather than soaps does