Conductometry Definitions and Applications Quiz

Conductometry Overview

• Conductance (G) measures an electrolyte solution's ability to carry electric current via ion movement in an electric field.
• Conductometry is an electrochemical analysis method that relies on measuring a solution's electrical conductivity.
• Conductometric analysis does not involve redox reactions.
• Different substances exhibit varying conductance levels, e.g., HCl has a different conductance compared to CH3COOH.

Ohm's Law and Conductance

• Ohm's Law formula: R = E/I, where R is resistance (Ohm), E is potential difference (Volt), and I is current (Ampere).
• Conductance (G) is defined as the inverse of resistance (G = 1/R).
• Units for conductance include Ohm–1, Siemens, or Moh.

Factors Affecting Conductance

• The conductance of a solution is influenced by several factors:
  • Nature of ions
  • Temperature
  • Concentration of ions
  • Size of the electrodes

Nature of Ions

• Ion characteristics (charge, size, hydration) affect their velocity and conductance.
• Higher ion charge increases its ability to carry current, enhancing conductance.
• Increased ionic size and hydration negatively impact ion velocity, leading to reduced conductance.

Temperature

• Increased temperature enhances conductance by decreasing viscosity and hydration.
• A temperature rise of 1°C can result in a 2% increase in conductance.
• Conductometric determinations must occur under consistent temperature conditions.

Concentration of Ions

• Conductance correlates directly with ion concentration; more ions lead to higher conductance.
• Highly concentrated solutions may exhibit non-linear conductance due to incomplete dissociation and interionic attractions.
• Activity coefficient (Fa) relates to concentration (C), defined as a = C × Fa, where Fa decreases as concentration increases.
• Thus, dilute solutions are preferred in conductometric determinations to ensure ions can move freely and carry current effectively.

Size of Electrodes

• Conductometric measurements are performed in a conductance cell featuring two parallel inert platinum electrodes.
• Conductance (G) is directly proportional to the electrode surface area (A) and inversely proportional to the distance (L) between electrodes.
• The relationship is summarized as G ∝ A and G ∝ 1/L, leading to the equation G = K.

Test your knowledge on conductometry with this quiz covering definitions such as conductance and conductometry, as well as applications of Ohm's law in the context of resistances in electrolyte solutions. The quiz is based on content by Dr. Aya M. Reda.