Question

When soap is added on an oily part of cloth, the hydrocarbon part of soap dissolves in

• A. Water, keeping the tail away from the oil
• B. Oil, keeping the head away from the oil
• C. Water, keeping the head away from the oil
• D. Oil, keeping the tail away from the oil

Hint:

Soaps clean by forming micelles where the tails trap oil and heads interact with water.

Answer 1

The Correct Option is B

Step 1: Structure of soap molecule.
A soap molecule consists of a long non-polar hydrocarbon tail and a polar ionic head.

Step 2: Action of soap on oily dirt.
The non-polar hydrocarbon tail dissolves in oil or grease, while the polar head remains in water.

Step 3: Orientation of soap molecules.
While dissolving oil, the hydrocarbon tail goes into the oil and the hydrophilic head stays away from the oil.

Step 4: Conclusion.
Therefore, the hydrocarbon part of soap dissolves in oil, keeping the head away from the oil.