The correct option is (c).
Explanation
Materials are classified as conductors or insulators based on their ability to allow electric current to flow through them. In solids, conductivity is primarily due to free electrons, whereas in liquids (electrolytes), it is determined by the presence and movement of ions.
Statement-wise Analysis:
- Statement 1 is Correct: Rubber and plastic are electrical insulators. They do not possess free electrons required to conduct electricity and are commonly used to cover electrical wires and tools to prevent electric shocks.
- Statement 2 is Incorrect: Lemon juice and vinegar contain weak acids (citric acid and acetic acid, respectively). These acids dissociate into ions in solution, making these liquids good conductors of electricity relative to insulators.
- Statement 3 is Correct: Water obtained from sources like hand pumps, wells, and taps is not pure; it contains small amounts of dissolved mineral salts. These dissolved salts provide ions that facilitate the flow of electric current, making such water a conductor. Conversely, distilled water is free of salts and is a poor conductor.
Key Takeaway:
Liquids containing dissolved acids, bases, or salts generally conduct electricity due to the presence of free ions. Pure water and solid insulators like rubber and plastic are poor conductors.