Soap (Chemistry Homework)

1. What is the chemical reaction in which the NaOH acts on the lard to produce soap?

2. What is unique about the soap molecule that allows it to remove dirt and grease, and dissolve in water?

3. Give the pH for: a strong acid, a weak acid, a neutral substance, a weak base, and a strong base. Where should your soap be?

4. What is the modern process for mass producing soap?


1. The saponification reaction can be written as below

C3H5(C18H35O2)3 + 3 NaOH → C3H5(OH)3 + 3 C17H35COONa

stearin + 3 sodium hydroxide → glycerol + 3 sodium stearate (soap)

2. The soap dissolved into water breaks down into ions. The organic part of the soap is hydrophylic and contains the carboxilate group. For this reason it is negatively charged. This way, this organic part into water bonds the dust on it by electrostatic attraction and washes.

3.for a strong acid the PH is below 3.5

for a weak acid the PH is between 7 and 3.5

for a neutral substance the PH is 7

for a weak base the PH is between 7 and 10.5

for a strong base the PH is between 10.5 and 14

4. the dissolved solution of soap into water is a weak base and has a PH between 9 and 10

5. The modern process for producing the soap is the so called cold process. in this process fats react with lye react at low temperature to produce soap. This process is different from the classic hot process (traditional) of saponification.