Surface Chemistry

At a given temperature, 0.45 g of acetic acid in 50 mL of water is shaken with 1.0 g of charcoal and the pH of the resulting solution is 3.0. Assume the adsorption of acetic acid from the aqueous solution by charcoal follows Freundlich isotherm,
$$\frac xm=kC^{1/n}$$
If the plot of $\log_{10}(x/m)$ against $\log_{10}C$ gives a straight line with slope 1, the value of $k$ in L mol$^{-1}$ is ____.

Given: The molar mass of acetic acid is 60 g mol$^{-1}$.
The acid dissociation constant of acetic acid is $1.0\times10^{-5}$ at the given temperature.
$x$ is the mass (in grams) of acetic acid adsorbed.
$m$ is the mass (in grams) of charcoal.
$C$ is the equilibrium concentration of acetic acid in the solution after the adsorption is complete.
$k$ and $n$ are constants for acetic acid-charcoal system at the given temperature.

Adsorption of phenol from its aqueous solution on to fly ash obeys Freundlich isotherm. At a given temperature, from $10\ \mathrm{mg\,g^{-1}}$ and $16\ \mathrm{mg\,g^{-1}}$ aqueous phenol solutions, the concentrations of adsorbed phenol are measured to be $4\ \mathrm{mg\,g^{-1}}$ and $10\ \mathrm{mg\,g^{-1}}$, respectively. At this temperature, the concentration (in $\mathrm{mg\,g^{-1}}$) of adsorbed phenol from $20\ \mathrm{mg\,g^{-1}}$ aqueous solution of phenol will be _____.

Use: $\log_{10}2 = 0.3$

To form a complete monolayer of acetic acid on 1 g of charcoal, 100 mL of 0.5 M acetic acid was used. Some of the acetic acid remained unadsorbed. To neutralize the unadsorbed acetic acid, 40 mL of 1 M NaOH solution was required. If each molecule of acetic acid occupies $\mathbf{P}\times10^{-23}\,\mathrm{m^2}$ surface area on charcoal, the value of P is _____.

[Use given data: Surface area of charcoal $= 1.5\times10^2\,\mathrm{m^2\,g^{-1}}$; Avogadro's number $(N_A) = 6.0\times10^{23}\,\mathrm{mol^{-1}}$]

Consider the following statements related to colloids.

(I) Lyophobic colloids are not formed by simple mixing of dispersed phase and dispersion medium.
(II) For emulsions, both the dispersed phase and the dispersion medium are liquid.
(III) Micelles are produced by dissolving a surfactant in any solvent at any temperature.
(IV) Tyndall effect can be observed from a colloidal solution with dispersed phase having the same refractive index as that of the dispersion medium.

The option with the correct set of statements is

The correct option(s) related to adsorption processes is(are)

Given below are two statements :

Statement I : Emulsions of oil in water are unstable and sometimes they separate into two layers on standing.

Statement II : For stabilisation of an emulsion, excess of electrolyte is added.

In the light of the above statements, choose the most appropriate answer from the options given below :

When 200 mL of 0.2 M acetic acid is shaken with 0.6 g of wood charcoal, the final concentration of acetic acid after adsorption is 0.1 M. The mass of acetic acid adsorbed per gram of carbon is ______ g.

Incorrect statement for Tyndall effect is :

Using very little soap while washing clothes, does not serve the purpose of cleaning of clothes, because :

2.0 g of $\mathrm{H_2}$ gas is adsorbed on 2.5 g of platinum powder at 300 K and 1 bar pressure. The volume of the gas adsorbed per gram of the adsorbent is ______ mL.

(Given : $R=0.083$ L bar K$^{-1}$ mol$^{-1}$)

Match List - I with List - II.

Choose the correct answer from the options given below :

If the initial pressure of a gas is 0.03 atm, the mass of the gas adsorbed per gram of the adsorbent is ______ $\times10^{-2}$ g.

The Zeta potential is related to which property of colloids ?

Match List - I with List - II :

Choose the correct answer from the options given below :

Which of the following is a correct statement ?

A 42.12% (w/v) solution of NaCl causes precipitation of a certain sol in 10 hours. The coagulating value of NaCl for the sol is

[Given: Molar mass : Na = 23.0 g mol$^{-1}$ ; Cl = 35.5 g mol$^{-1}$]

100 mL of 0.3 M acetic acid is shaken with 0.8 g of wood charcoal. The final concentration of acetic acid in the solution after adsorption is 0.125 M. The mass of acetic acid adsorbed per gram of carbon is ______ $\times10^{-4}$ g.

(Given : Molar mass of acetic acid = 60 g mol$^{-1}$)

Match List - I with List - II

Choose the correct answer from the options given below :

For micelle formation, which of the following statements are correct ?

A. Micelle formation is an exothermic process.

B. Micelle formation is an endothermic process.

C. The entropy change is positive.

D. The entropy change is negative.

Match List - I with List - II.

Choose the correct answer from the options given below :