Correct Option
The correct option is 1 and 2 only.
Explanation
Electrical conductivity in aqueous solutions is determined by the presence and mobility of ions. Substances that dissociate into ions when dissolved in water are called electrolytes, while those that do not form ions are non-electrolytes. The flow of electric current in a solution requires free-moving charged particles.
Statement-wise Analysis
- Statement 1 is Correct: Glucose ($C_6H_{12}O_6$) and alcohol ($C_2H_5OH$) are covalent compounds. When dissolved in water, they do not dissociate into ions but remain as neutral molecules. Due to the absence of charge carriers (ions), these solutions do not conduct electricity.
- Statement 2 is Correct: Acidic solutions contain acids (like $HCl$ or $H_2SO_4$) which ionize in water to release hydrogen ions ($H^+$) or hydronium ions ($H_3O^+$) and anions. These free-moving ions facilitate the flow of electric current through the solution.
- Statement 3 is Incorrect: It is factually incorrect to state that all covalent compounds conduct electricity. While polar covalent compounds like acids ionize and conduct, most covalent compounds (such as sugar, urea, and alcohol) do not ionize in water and act as non-conductors.
- Statement 4 is Incorrect: Pure (distilled) water is a very weak electrolyte with a negligible degree of ionization. It contains an extremely low concentration of ions ($H^+$ and $OH^-$), making it a poor conductor of electricity. Water conducts electricity effectively only when salts or other impurities are dissolved in it.
Key Takeaway
Key Takeaway: The electrical conductivity of a solution depends on ionization. Acids, bases, and salts dissociate into ions and conduct electricity (electrolytes), whereas covalent organic compounds like glucose and alcohol do not produce ions and are non-conductors.