Question

Soap solution is added to the aqueous solutions of sodium chloride, calcium chloride, potassium chloride and magnesium chloride in four different test tubes and the contents are shaken well. In which two test tubes will enough lather not be formed? Why?

Answer 1

Soap forms insoluble precipitates with calcium and magnesium ions forming a scum. Hence, test tube containing potassium chloride, calcium chloride and magnesium chloride respectively will form scum.

the good amount of lather is formed in kcl and Nacl solutions.

Because these solutions are hard watered.

Answer 2

● When soap solution is added to the aqua solution in the test tube containing sodium chloride and potassium chloride good amount of leather is formed.

● When soap solution is added to the aqua solution of magnesium chloride and calcium chloride insoluble precipitate is formed due to the reaction of solids and forms scum.

● The formation of scum is due to the hardness of water because of magnesium and Calcium salts.