Surface Chemistry

Peptisation involves

• precipitation of colloidal particles

• disintegration of colloidal aggregates

• evaporation of dispersion medium

• impact of molecules of the dispersion medium on the colloidal particles

In Langmuir's model of adsorption of a gas on a solid surface,

• the rate of dissociation of adsorbed molecules from the surface does not depend on the surface covered

• the adsorption at a single site on the surface may involve multiple molecules at the same time

• the mass of gas striking a given area of surface is proportional to the pressure of the gas

• the mass of gas striking a given area of surface is independent of the pressure of the gas

Which one of the following is most effective in causing the coagulation of an As₂S₃ sol?

• KCl

• AlCl₃

• MgSO₄

• K₃Fe(CN)₆

The continuous phase contains the dispersed phase throughout, example is

• water in milk

• fat in milk

• water droplets in mist

• oil in water

Peptization denotes

• digestion of food

• hydrolysis of proteins

• breaking and dispersion into colloidal state

• precipitation of solid from colloidal dispersion

Blue colour of water in sea is due to

• refraction of blue light by impurities

• refraction blue sky by water

• scattering of light by water

• None of the above

Freundlich adsorption isotherm is

• $\frac{\mathrm{x}}{\mathrm{m}}={\mathrm{kp}}^{1/\mathrm{n}}$

• $\mathrm{x}={\mathrm{mkp}}^{1/\mathrm{n}}$

• $\frac{\mathrm{x}}{\mathrm{m}}={\mathrm{kp}}^{-\mathrm{n}}$

• All of these

In ...... process, work is done at the expense of internal energy.

• isothermal

• isochoric

• adiabatic

• isobaric

Haber process is used for the production of which of the following?

• NH₃

• HNO₃

• H₂SO₄

• O₃

Which of the following is not true about a catalyst?

• Mechanism of the reaction in presence and absence of catalyst could be different.

• Use of catalyst cannot change the order of the reaction

• Catalyst enhances both forward and backwards reaction at equal rate.

• Catalyst participates in the reaction, but not consumed in the process.