Electrical Conductivity Test

Introduction to Electrolytes

• Electrolytes are substances that, when dissolved in water, produce ions that conduct electricity.

• A common misconception is that electrolytes generate electricity; instead, they facilitate the flow of electricity through ions.

Demonstration Setup

• The demonstration uses a light bulb tester connected to two electrodes submerged in a solution.

• Plain water, which has few charged particles, does not allow electricity to flow.

Strong Electrolytes

• Sodium chloride (NaCl) is introduced as a strong electrolyte.

• When NaCl is added to water, it completely dissociates into sodium ions (Na⁺) and chloride ions (Cl⁻).

• The presence of these ions allows for a bright light bulb, indicating a high level of conductivity.

Non-Electrolytes

• Sucrose (table sugar) is used to illustrate a non-electrolyte.

• Although sucrose dissolves in water, it does not dissociate into ions; thus, the light bulb does not light up.

• This lack of ion production signifies that sucrose cannot conduct electricity.

Weak Electrolytes

• Acetic acid (HC₂H₃O₂), found in vinegar, is presented as a weak electrolyte.

• When dissolved in water, acetic acid partially dissociates into hydrogen ions (H⁺) and acetate ions (C₂H₃O₂⁻).

• The light bulb lights up but is dim, demonstrating that only a small proportion of acetic acid molecules dissociate compared to strong electrolytes.

Comparison of Electrolytes

• Strong electrolytes exhibit complete dissociation, resulting in a high concentration of ions that effectively conduct electricity.

• Weak electrolytes show partial dissociation, leading to fewer ions and therefore lower conductivity.

• Non-electrolytes do not dissociate into ions at all, resulting in no electrical conductivity.

Conclusion

• The ability of a substance to conduct electricity in solution is contingent upon the production of ions when dissolved in water.

• The electricity in the demonstration comes from an external power supply, not from the solution itself.

• Safety precautions are advised when handling substances like acetic acid.