The question asks which parameters in the Nernst-Planck equation govern chloride migration. The options are: A. Concentration gradient B. Binding isotherm C. Electrical potential D. Convection velocity E. Temperature

1. Problem Description

The question asks which parameters in the Nernst-Planck equation govern chloride migration. The options are:

A. Concentration gradient

B. Binding isotherm

C. Electrical potential

D. Convection velocity

E. Temperature

2. Solution Steps

The Nernst-Planck equation describes the flux of ions under the influence of a concentration gradient and an electrical field. The equation is often written as:

$J_i = -D_i \frac{dc_i}{dx} - z_i u_i c_i \frac{d\phi}{dx} + c_i v$

Where:

$J_i$ is the flux of ion $i$

$D_i$ is the diffusion coefficient of ion $i$

$\frac{dc_i}{dx}$ is the concentration gradient of ion $i$

$z_i$ is the valence of ion $i$

$u_i$ is the mobility of ion $i$

$c_i$ is the concentration of ion $i$

$\frac{d\phi}{dx}$ is the electrical potential gradient

$v$ is the convection velocity

From the equation, we can see that the flux $J_i$ is dependent on the concentration gradient ($\frac{dc_i}{dx}$), and electrical potential gradient ($\frac{d\phi}{dx}$). The convective term $c_i v$ also directly affects the flux. Temperature affects the diffusion coefficient $D_i$ according to the Stokes-Einstein relation, and it affects the ion mobility $u_i$.

Binding isotherm relates the concentration of a solute adsorbed onto a surface to the concentration of the solute in the solution. It is not directly a parameter in the Nernst-Planck equation.

Therefore, the parameters that govern chloride migration are concentration gradient, electrical potential, convection velocity and temperature.

3. Final Answer

A. Concentration gradient

C. Electrical potential

D. Convection velocity

E. Temperature