Question

Resistance of decimolar solution between 2 electrode which are 0.02 m apart and 0.0004 m² in area was found to be 50 ohm. Specific conductance is ______ (in Sm⁻¹)

Answer 1

1

Answer 2

To determine the specific conductance (κ), we use the relationship between resistance (R), resistivity (ρ), length (l), and area (A), and the definition of specific conductance.

1. Relate Resistance to Resistivity: The resistance of a conductor is given by the formula: $R = \rho \frac{l}{A}$ where:

   • R = Resistance = 50 ohm
   • ρ = Resistivity
   • l = Distance between electrodes = 0.02 m
   • A = Area of electrodes = 0.0004 m²

2. Define Specific Conductance: Specific conductance (κ) is the reciprocal of resistivity (ρ): $\kappa = \frac{1}{\rho}$

3. Derive the formula for Specific Conductance: From the resistance formula, we can express resistivity as: $\rho = R \frac{A}{l}$ Substitute this into the specific conductance definition: $\kappa = \frac{1}{R \frac{A}{l}} = \frac{l}{R A}$

4. Calculate Specific Conductance: Substitute the given values into the derived formula: $\kappa = \frac{0.02 \text{ m}}{50 \text{ ohm} \times 0.0004 \text{ m}^2}$ $\kappa = \frac{0.02}{0.02} \text{ Sm}^{-1}$ $\kappa = 1 \text{ Sm}^{-1}$

The specific conductance is 1 Sm⁻¹.