Question

Which of the following factor(s) will determine the electrolytic conductance of a solution?

• A. Nature of electrolyte
• B. Solute - solvent interaction
• C. Solute - solute interaction
• D. Charge and size of the ions

Answer 1

Answer: (A), (B), (C), (D)

Charge and size of the ions

Factor affecting electrolytic conductance/resistance:
(a) Solute- Solute interaction:
When inter–ionic force of attraction​ between solute is higher, the resistance will be higher. Thus, lower will be the conductance.
$\text{Attractive force}\propto \text{Charge of ions}$

At higher concentration, ​the force of attraction ​between the ions increases which decreases the ​speed of the ions​. Hence, conductance decreases with increase in concentration​.

(b) Solute - solvent interaction:
It is an interaction of a solute with the solvent. It restricts the free motion of ions, thus, decreasing conductance​. It is actually the solvation/ hydration of ions​.

Greater the solvation​, greater will be the resistance.

$\text{Solvation}\propto \text{Change on ions}\propto \frac{1}{\text{Size}}$

Smaller the size of ions, greater will be the solvation. Thus, the resistance will be higher and conductance will be lower.

On dilution, the solute - solvent interactions decrease​. Thus, the ionic mobility and ​conductance increases.​

(c) Nature of electrolyte:
Weak electrolyte will have high resistance and low conductance​ becuase they do not undergo complete dissociation.

Strong electrolyte will have low resistance and high conductance​ becuase they undergo complete dissociation.

Thus, all the given factors will determine the electrolytic conductance of a solution.