Medium INTEGER +4 / -1 PYQ · JEE Mains 2021

CH4 is absorbed on 1g charcoal at 0$^\circ$C following the Freundlich adsorpiton isotherm 10.0 mL of CH4 is adsorbed at 100 mm of Hg, whereas 15.0 mL is adsorbed at 200 mm of Hg. The volume of CH4 adsorbed at 300 mm of Hg is 10x mL. The value of x is _________ $\times$ 10-2.

(Nearest integer) [Use log102 = 0.3010, log103 = 0.4771]

Answer (integer) 128

Solution

We know<br><br>${x \over m} = K{P^{1/n}}$; using (x $\propto$ V)<br><br>$\Rightarrow {{10} \over 1} = K \times {(100)^{1/n}}$ ..... (1)<br><br>${{15} \over 1} = K \times {(200)^{1/n}}$ ..... (2)<br><br>${V \over 1} = K \times {(300)^{1/n}}$ ..... (3)<br><br>Divide<br><br>(2) / (1)<br><br>${{15} \over {10}} = {2^{1/n}}$<br><br>$\log \left( {{3 \over 2}} \right) = {1 \over n}\log 2$<br><br>$${1 \over n} = {{\log 3 - log2} \over {\log 2}} = {{0.4771 - 0.3010} \over {0.3010}}$$<br><br>${1 \over n} = 0.585$<br><br>Divide<br><br>(3) / (1)<br><br>${V \over {10}} = {3^{1/n}}$<br><br>$\log \left( {{V \over {10}}} \right) = {1 \over n}\log 3$<br><br>$\log \left( {{V \over {10}}} \right) = 0.585 \times 0.4771 = 0.2791$<br><br>${V \over {10}} = {10^{0.279}} \Rightarrow V = 10 \times {10^{0.279}}$<br><br>$\Rightarrow V = {10^{1.279}} = {10^x}$<br><br>$\Rightarrow$ x = 1.279<br><br>$\Rightarrow$ x = 128 $\times$ 10<sup>$-$2</sup> (Nearest integer)

About this question

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

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