Which of the following sets comprises liquids which are poor conductors of electricity ?

The correct option is shampoo, vegetable oil, distilled water.

Liquids conduct electricity primarily due to the presence of free-moving ions. Let's analyze the electrical conductivity of the given liquids:

1. Distilled Water: Distilled water is pure water that is free from dissolved salts, minerals, and ions. Because it lacks free ions, it does not conduct electricity and is a poor conductor (insulator).

2. Vegetable Oil: Vegetable oil consists of covalent molecular compounds (triglycerides) that do not dissociate into ions in liquid form. Without free charge carriers, vegetable oil is a poor conductor of electricity.

3. Shampoo: Most commercial shampoos contain chemical compounds that do not produce sufficient free ions for good electrical conduction compared to electrolyte solutions like salt water or acid solutions. Thus, shampoo acts as a poor conductor of electricity.

In contrast, liquids like tap water, salt solution, lemon juice, and vinegar contain dissolved mineral salts or acids that dissociate into free ions, making them good conductors of electricity.

Therefore, the set comprising liquids that are poor conductors of electricity is shampoo, vegetable oil, distilled water.