Materials required:
- Vegetable oil (castor oil, olive oil, coconut oil or palm oil)
- 20% sodium hydroxide solution
- Common salt
- Measuring cylinders
- Glass beaker (250 ml)
- Blue and red litmus papers
- Glass rod
- Bunsen burner
- Wire gauze
- Tripod stand
- Filter funnel
- Filter paper
- Spatula
- Knife
Fat or Oil + Alkali → Soap + Glycerol
Procedure:
- Take 25 ml of coconut oil in a measuring cylinder and pour it into a 250 ml glass beaker.
- Measure 30 ml of 20% NaOH solution in another measuring cylinder and add it into the beaker containing vegetable oil.
- Vigorously stir the mixture using a glass rod.
- Touch the beaker from outside. It is observed that the beaker is warm.
- Place the beaker on a wire gauze placed over a tripod stand.
- Heat the beaker using a Bunsen burner till the mixture become a whitish paste.
- Remove the beaker from the flame and allow it to cool.
- Dip a red litmus paper in the suspension formed.
- When dipped in the suspension, the red litmus paper changes its color to blue.
- Dip a blue litmus paper in the suspension.
- The color of blue litmus paper remains the same.
- To the above suspension, add 15g of common salt and stir it well with a glass rod.
- After adding common salt, soap in the suspension gets precipitated out as solid.
- Take a filter funnel and place a filter paper in it and fix it in a stand.
- Place a beaker below the funnel.
- Pour the contents of the beaker into the funnel over a glass rod and filter the contents of the beaker.
- After filtration, soap is left behind in the filter paper.
- Transfer the soap into another filter paper using a spatula and dry it by pressing with another filter paper.
- Then, cut it into the desired shape with a knife and you can add fragrance to soap before they got solid shape.
