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Activity 4.7 — Soap Preparation (Saponification)
NCERT Activity 4.7: Prepare soap by saponification of vegetable oil with NaOH. Then compare soap vs detergent behavior in hard water.
How To Perform
1
Heat Oil + NaOH
Heat vegetable oil with NaOH solution to start saponification.
2
Add Salt
Add common salt to precipitate the soap ('salting out').
3
Observe Soap
Collect the soap curd and observe the glycerol remaining.
4
Hard Water Test
Compare soap vs detergent in hard water — discover why detergents win!
⚠️ Safety Notes
- •NaOH (caustic soda) is highly corrosive — wear gloves and eye protection.
- •Hot oil can cause severe burns — use tongs and heat-resistant gloves.
- •Do not taste the soap — it is harsh and contains residual NaOH.
- •Work in a well-ventilated area — heating NaOH produces fumes.