Govt Exams
In molten NaCl electrolysis, Na⁺ is reduced at cathode to Na metal. Cl⁻ is oxidized to Cl₂ at anode. Water is absent, so no oxygen evolution.
Upon dilution, the degree of ionization increases due to reduced ion-ion interactions (interionic forces), leading to more free ions and higher molar conductivity.
When E°cell > 0, the cell reaction is spontaneous. ΔG° = -nFE°cell is negative, indicating spontaneity.
The fundamental relationship is ΔG° = -nFE°cell, where n is number of electrons, F is Faraday constant (96485 C/mol), and E°cell is standard cell potential.
In electroplating, the object to be plated is made the cathode (negative terminal) where reduction occurs, causing metal deposition.
A dry cell or Leclanche cell is a primary cell that cannot be recharged. Lead-acid and Ni-Cd are secondary cells; Li-ion is rechargeable.
The Nernst equation: E = E° - (RT/nF)ln(Q) calculates the cell potential when concentrations are not at standard state (1 M).
Faraday's first law states that the mass of substance deposited/dissolved during electrolysis is directly proportional to the quantity of electricity (charge) passed through the electrolyte.
In a galvanic cell, the anode is the negative electrode where oxidation occurs. The cathode is positive where reduction occurs.
Electrical conductivity is measured in Siemens per meter (S·m⁻¹). Ω·m is the unit of resistivity, which is the inverse of conductivity.