Metallic vs. Electrolytic Conductors
Conductors are substances that allow the flow of electric current. However, the mechanism of conduction differs significantly depending on whether the material is a metal or an electrolyte.
| Property | Metallic Conductors | Electrolytic Conductors |
|---|---|---|
| Charge Carriers | Flow of free electrons. | Movement of ions (cations and anions). |
| Physical State | Usually occurs in solids (metals and graphite). | Occurs in molten state or aqueous solutions. |
| Chemical Change | No chemical change occurs in the conductor. | Chemical decomposition occurs at electrodes (electrolysis). |
| Transfer of Matter | No transfer of matter involved. | Involves the physical transfer of ions. |
| Resistance | Due to collisions of electrons with metal kernels. | Due to inter-ionic attraction and solvent viscosity. |
| Temperature Effect | Conductivity decreases as temperature rises. | Conductivity increases as temperature rises. |
| Examples | Copper, Aluminum, Silver, Iron. | NaCl solution, H2SO4, molten KCl. |
Summary: Temperature vs. Conduction
The effect of temperature on electrical conductivity depends entirely on whether the charge carriers are electrons or ions:
- Metallic Conduction (Physical Process): As temperature increases, metal lattice vibrations increase. This disrupts the path of the free electrons, creating resistance and decreasing overall conductivity.
- Electrolytic Conduction (Chemical Process): As temperature increases, the kinetic energy of the ions increases. This reduces the viscosity of the solvent, increases ionic mobility, and increases overall conductivity.
Exam Shortcut: Temperature ↑ → Metallic Conductivity ↓ but Electrolytic Conductivity ↑.