259. Distinguish between: (a) Electrolytes and non-electrolytes, (b) Reduction potential and oxidation potential (c) Primary cells and secondary cells, (d) Specific conductivity and molar conductivity.

electrolytes

nonelectrolyte

An electrolyte dissociates in solution and thus produce ion.

A nonelectrolyte does not dissociate at all in solution and therefore does not produce any ions.

Electrolytes are ionic  substance that dissolve in water

Nonelectrolytes are typically polar covalent substances that do dissolve in water as molecules instead of ions.

Primary cell

Secondary

Lower initial cost.

Higher Initial Cost

Higher life-cycle cost ($/kWh).

Lower life-cycle cost ($/kWh) if charging in convenient and inexpensive

Disposable.

Regular maintenance required.

Typically lighter and smaller  thus traditionally more suited for portable applications.

Traditionally less suited for portable applications, although recent advances in Lithium battery technology have lead to the development of smaller/lighter secondary batteries.

Molar conductivity

Specific conductivity

Molar Conductivity of a solution at a given concentration is the conductance of the volume V of solution containing one mole of electrolyte kept between two electrodes with area of cross section A and distance of unit length. Therefore,

Distance is unit  so l = 1

Volume          = area of base × length

So V   = A × 1  = A

Λ_m       =κA/l

Λ_m       = κV

Conductivity of a solution is equal to the conductance of a solution of 1 cm length

and cross section area of 1 square cm.  it may also be define as the conductance of ine centimeter cube of the conductor . It is represented by the symbol Kappa (κ). mathematically we can write

κ = 1/ p

here ρ is resistivity

the unit of K is ohm ^–1 cm ^–1 or S cm^–1

The conductivity, κ, of an electrolytic solution depends on the concentration of the electrolyte, nature of solvent and temperature.