Q25 / 90 · KVPY 2011 (SB/SX) · Chemistry

The adsorption isotherm for a gas is given by the relation $x=a p /(1+b p)$ where $x$ is moles of gas adsorbed per gram of the adsorbent, $p$ is the pressure of the gas, and a and $b$ are constants. Then $x$

  • A
    increases with $\mathrm{p}$
  • B
    remains unchanged with $\mathrm{p}$
  • C
    decreases with $\mathrm{p}$
  • Correct answer
    D
    increases with $\mathrm{p}$ at low pressures and then remains the same at high pressure

Solution

According to Lagmuir curve $\mathrm{x}=\frac{\mathrm{ap}}{1+\mathrm{bp}}$ $\begin{array}{ll}\mathrm{p} \rightarrow \infty & \mathrm{x}=\frac{\mathrm{a}}{\mathrm{b}} \\ \mathrm{p} \rightarrow 0 & \mathrm{x} \propto \mathrm{p}\end{array}$

Hence, the correct answer is option: 'D'.

More Surface Chemistry Questions