Diffusion Coefficient given Diffusion Current Calculator

Diffusion Coefficient Formula:

\[ D = \left( \frac{I_d}{607 \times n \times m_r^{2/3} \times t^{1/6} \times c} \right)^2 \]

Diffusion Current (I_d):

Number of Electrons (n):

Mass Flow Rate (m_r):

kg/s

Time for Dropping Mercury (t):

Concentration (c):

mol/m³

Diffusion Coefficient (D): m²/s

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1. What is Diffusion Coefficient given Diffusion Current?

Definition: This calculator determines the diffusion coefficient (D) using the Ilkovic equation based on measured diffusion current and other parameters.

Purpose: It helps electrochemists and researchers analyze polarographic measurements and understand diffusion processes in electrochemical systems.

2. How Does the Calculator Work?

The calculator uses the Ilkovic equation:

\[ D = \left( \frac{I_d}{607 \times n \times m_r^{2/3} \times t^{1/6} \times c} \right)^2 \]

Where:

\( D \) — Diffusion coefficient (m²/s)
\( I_d \) — Diffusion current (A)
\( n \) — Number of electrons transferred
\( m_r \) — Mass flow rate of mercury (kg/s)
\( t \) — Drop time (s)
\( c \) — Concentration of depolarizer (mol/m³)

Explanation: The equation relates the diffusion current measured in polarography to the diffusion coefficient of the electroactive species.

3. Importance of Diffusion Coefficient Calculation

Details: The diffusion coefficient is crucial for understanding mass transport in electrochemical systems, reaction kinetics, and designing electrochemical experiments.

4. Using the Calculator

Tips: Enter all parameters with correct units. Typical values:

Diffusion current: microamperes (10⁻⁶ A)
Mass flow rate: milligrams per second (10⁻⁶ kg/s)
Drop time: 2-6 seconds
Concentration: millimoles per liter (1 mol/m³ = 1 mM)

5. Frequently Asked Questions (FAQ)

Q1: What is the significance of the constant 607?
A: This constant combines several fundamental constants and conversion factors specific to mercury electrodes in the Ilkovic equation.

Q2: How does temperature affect the diffusion coefficient?
A: Diffusion coefficient increases with temperature (typically 2-3% per °C), but this calculator assumes standard conditions.

Q3: What's a typical range for diffusion coefficients?
A: For most ions in aqueous solutions at 25°C, D ranges from 0.5×10⁻⁹ to 2×10⁻⁹ m²/s.

Q4: Why is mercury used in polarography?
A: Mercury's reproducible surface, wide potential window, and renewable electrode surface make it ideal for polarographic measurements.

Q5: How accurate is the Ilkovic equation?
A: It provides good approximations for spherical diffusion to small mercury drops, though modern refinements exist for greater precision.