Question

Why is it necessary to platinize the electrodes of a conductivity cell before it is used for conductance measurement?

Answer 1

Platinizing electrodes of a conductivity cell means covering them with a layer of platinum black.

We do so because platinization increases the surface area of the electrode on which the hydrogen gas can be in contact with hydrogen ions (which are the conducting aqueous ions). This means that the reaction happens faster, leading to a better conductance measurement.