Soaps are less soluble in hard water why?

Grease and oil are non>polar and insoluble in water. These fatty acids are less soluble than the sodium or potassium salts and form a precipitate or soap dirt. Because of this, soaps are ineffective in acidic water. Also, soaps form insoluble salts in hard water, such as water containing magnesium, calcium, or iron.

the potential energy of the reactants is 200j.

from the energy diagram, the energy of the product formed is 350j; this means that, this reaction is an endothermic reaction, because it absorbs energy from its environment.