Correct Option
The correct option isVinegar
Explanation
The deflection of a magnetic compass needle placed near a wire in a closed circuit is caused by the magnetic effect of electric current. For the needle to deflect, electric current must flow through the circuit. When a liquid is part of the circuit, it must be an electrolyte-a substance that dissociates into ions to conduct electricity.
Option Analysis
- Distilled water Distilled water: Distilled water is chemically pure and free of dissolved salts or minerals. It does not contain free-moving ions and acts as an electrical insulator. Consequently, no current flows, and the needle does not deflect.
- Vegetable oil Vegetable oil: Vegetable oil consists of non-polar organic molecules. It does not dissociate into ions and acts as an insulator, preventing the flow of current.
- Vinegar: Vinegar is a solution of acetic acid ($CH_3COOH$) in water. It acts as an electrolyte by dissociating into hydrogen ions ($H^+$) and acetate ions ($CH_3COO^-$). These mobile ions facilitate the flow of electric current through the liquid, generating a magnetic field that causes the compass needle to deflect.
- Honey: Honey is primarily composed of sugars (covalent compounds like glucose and fructose). It does not dissociate into ions significantly and is a poor conductor of electricity compared to an electrolyte like vinegar.
Key Takeaway: For a liquid to conduct electricity and complete a circuit (allowing the magnetic effect of current to be observed), it must contain free ions. Solutions of acids, bases, and salts are common electrolytes.