The correct option is (c) 1 and 3 only.
Explanation
The conduction of electricity in liquids differs from that in solids. In solids (metals), conduction is due to the flow of free electrons. In liquids, conduction depends on the presence of free ions (charged particles) that can move through the solution. Liquids that conduct electricity are known as electrolytes.
Statement-wise Analysis
- Statement 1 is Correct: Pure liquids often do not conduct electricity well because they lack free charge carriers. However, when acids, bases, or salts are dissolved in water, they dissociate into positive and negative ions. These ions act as charge carriers, allowing electric current to pass through the solution. Therefore, most conductive liquids are solutions of acids, bases, or salts.
- Statement 2 is Incorrect: Distilled water is a poor conductor of electricity because it is free of salts and minerals, meaning it lacks free ions. When common salt (Sodium Chloride, NaCl) is dissolved in distilled water, it dissociates into sodium ions (Na+) and chloride ions (Cl-). The presence of these free-moving ions makes the solution a good conductor of electricity, not an insulator.
- Statement 3 is Correct: Lemon juice contains citric acid. When added to distilled water, the acid dissociates to release ions into the solution. These ions facilitate the flow of electric current, transforming the non-conductive distilled water into a conductor.
Key Takeaway: Electrical conductivity in liquids requires the presence of free ions. Distilled water is an insulator due to the absence of ions, but it becomes a conductor when electrolytes such as acids, bases, or salts are dissolved in it.