TITLE: Organic Chemistry
AIM: To prepare a sample of soapy detergent (soap)
APPARATUS: 4 mol sodium hydroxide, oil, beaker, conical flask, measuring cylinder, filter funnel,
filter paper, Bunsen burner, tripod stand, wire gauze, NaCl (sodium chloride), spatula, distilled water
PRODECURE:
1. Place 4cm3 of oil (e.g. castor or corn) and 20cm3 4 mol dm- sodium hydroxide into a 250cm3
conical flask
2. Gently boil the mixture on a water bath for 15 minutes, stirring and topping up with water as
required, then allow to cool.
3. Add two spatulas of sodium chloride, stir well, filter off the solution and wash with a little
cold distilled water. The solid is a sample of soap.
4. Shake a little of the solid with:
a. Warm tap water
b. Warm distilled water
Compare the results.
RESULTS: When the oil and sodium hydroxide were placed in the water bath,it formed a white
precipitate. After the solution was placed in the filter funnel, the white precipitate remained on the
filter paper and was solidified after being left to dry. When placed in the distilled water, the sample
of soap produced a lot of lather while when it was placed in the tap water, it did not produce much
lather at all.
ANALYSIS: In Chemistry, a detergent is defined as any group of synthetic, water-soluble, liquid or
organic cleansing agent that is chemically different from soap but is still able to emulsify oils, hold
dirt in suspension and act as a wetting agent. Detergents may be separated into two different
groups; soapy and soapless. Soapy detergents are made from reacting natural esters with an alkali
and can usually come in bars and is biodegradable while soapless detergents are made from
petroleum products that have been treated with sulphuric acid, making them non-biodegradable
and usually comes in liquid form. To make a soap, the process of saponification must occur. In this
process, triglycerides in fats or oils react with aqueous NaOH (Fat + 3NaOH ⇌ Glycerol + sodium salts
(soap)) to be converted into soap or glycerol. In this experiment,
a) 2RCOO-Na+ + Ca2+  (RCOO)2Ca + 2Na+
SOURCES OF ERROR:
1. Adding too much salt to the solution
2. Tearing the filter paper when stirring
3. Taking the solution off the Bunsen burner too soon
LIMITATIONS:
1.
PRECAUTIONS:
1. Measuring out the salt exactly
2. Carefully stirring the stirring rod in the filter funnel and ensuring not to spill over or touch
the filter paper
3. Timing the solution on the burner exactly
CONCLUSION: We were able to produce a sample of soap and tested it in the two types of water to
observe whether it would lather or not.
REFLECTION: This experiment was very simple and interesting as watching the soap begin to congeal
and coming back to it after it dried was quite a scene. It was nice because I felt like an actual chemist
who was researching a topic. It, also, helped me to remember things that we learnt in classes and
apply them to what we were doing for the experiment.