Question

In Freundlich adsorption isotherm, slope of AB line is :

• A. $\log n$ with $( n >1)$
• B. $n$ with $( n , 0.1$ to 0.5$)$
• C. $\log \frac{1}{n}$ with $(n<1)$
• D. $\frac{1}{ n }$ with $\left(\frac{1}{ n }=0\right.$ to $\left.1\right)$

Answer 1

The Correct Option is D

The Freundlich adsorption isotherm is a scientific formula that helps describe how solutes interact with surfaces. It is typically written as:

\(x/m = k \cdot C^{\frac{1}{n}}\)

where:

• \(x/m\) is the amount of adsorbate per unit mass of adsorbent.
• \(C\) is the concentration of the solute in the solution.
• \(k\) and \({1}/{n}\) are constants.
  
  

To align with experimental data, we often convert this into a logarithmic form:

\(\log\left(\frac{x}{m}\right) = \log(k) + \frac{1}{n} \log(C)\)

In this equation, \(\log(k)\) is the intercept and \(\frac{1}{n}\) is the slope of the line obtained in a plot of \(\log(x/m)\) versus \(\log(C)\). In the options given, the correct answer relates to this slope.

The correct answer is:

• \(\frac{1}{n}\) with \(\left(\frac{1}{ n }=0\right.\) to \(\left.1\right)\)

This is because the slope in the logarithmic form of the Freundlich isotherm is exactly \(\frac{1}{n}\), and \(\frac{1}{n}\) typically ranges between 0 and 1. This reflects the effectiveness of adsorption — if \(n > 1\), it means that adsorption is favorable across a wide range of concentrations.