Easy INTEGER +4 / -1 PYQ · JEE Mains 2020

The mass of gas adsorbed, x, per unit mass of adsorbate, m, was measured at various pressures, p. A graph between $\log {x \over m}$ and log p gives a straight line with slope equal to 2 and the intercept equal to 0.4771. The value of ${x \over m}$ at a pressure of 4 atm is :
(Given log 3 = 0.4771)

Answer (integer) 48

Solution

According to Freundlich adsorption isotherm, in the median range of pressure <br><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;${x \over m} \propto {P^{{1 \over n}}}$ <br><br>$\Rightarrow$&nbsp;&nbsp;${x \over m}$ = kP$^{{1 \over n}}$ ....(1) <br><br>taking log both sides, we get, <br><br>log${x \over m}$ = logk + ${1 \over n}$ logP <br><br>Here in graph between log${x \over m}$ and logP, slope is ${1 \over n}$ and intercepts = log k. <br><br>Given, log k = 0.4771 $\Rightarrow$ k = 3 <br><br>Slope ${1 \over n}$ = 2 <br><br>put in eq. (1), ${x \over m}$ = 3 $\times$ (4)<sup>2</sup> = 48

About this question

Subject: Chemistry · Chapter: Surface Chemistry · Topic: Adsorption

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