Academic Experts Solutions for Chapter: Surface Chemistry, Exercise 2: KVPY PROBLEMS (PREVIOUS YEARS)

A gel toothpaste is a mixture of a:

A water droplet spreads on a clean gold surface. The droplet, however, does not spread onto a gold surface, which is pre-treated with a dilute solution of hexanethiol $\left[\mathrm{CH}{}_3-{\left({\mathrm{CH}}_2\right)}_5-\mathrm{SH}\right]$ and washed with excess water. This is because

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

Emulsification of $10 \mathrm{ml}$ of oil in water produces $2.4\times {10}^{18}$ droplets. If the surfaces tension at the oil-water interface is $0.03 {\mathrm{Jm}}^{-2}$ and the area of each droplet is $12.5\times {10}^{-16} {\mathrm{m}}^2$, the energy spent in the formation of oil droplets is :

Consider the following statements about Langmuir isotherm:

$\left(\mathrm{i}\right)$ The free gas and adsorbed gas are in dynamic equilibrium.

$\left(\mathrm{ii}\right)$ All adsorption sites are equivalent.

$\left(\mathrm{iii}\right)$The initially adsorbed layer can act as a substrate for further adsorption.

$\left(\mathrm{iv}\right)$The ability of a molecule to get adsorbed at a given site is independent of the occupation of neighbouring sites.

The correct statements are: