A catalyst increases the rate of reaction because it:

1. Increases the activation energy

2. Decreases the energy barrier for the reaction

3. Decreases the collision diameter

4. Increases the temperature coefficient

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

(1) the rate of dissociation of adsorbed molecules from the surface does not depend on the surface covered

(2) the adsorption at a single site on the surface may involve multiple molecules at the same time

(3) the mass of gas striking a given area of surface is proportional to the pressure of the gas

(4) the mass of gas striking a given area of surface is independent of the pressure of the gas

Rate of physisorption increases with:

(1) Decrease in temperature

(2) Increase in temperature

(3) Decrease in pressure

(4) Decrease in surface area

Adsorption of a gas on solid metal surface is spontaneous and exothermic, then:

(1) H increases

(2) S increases

(3) G increases

(4) S decreases

Identify the correct statement regarding enzymes:

(1) Enzymes are specific biological catalyst that possess well defined active states

(2) Enzymes are normally heterogeneous catalyst that are very specific in their action

(3) Enzymes are specific biological catalysts that can not be poisoned

(4) Enzymes are specific biological catalysts that can normally function at very high temperature (T$\simeq$1000K)

Which of the following statements is incorrect regarding physisorptions?

(1) More easily liquefiable gases are adsorbed readily

(2) Under high pressure it results into multimolecular layer on the adsorbent surface

(3) Enthalpy of adsorption ($∆H_{adsorption}$) is low and positive

(4) It occurs because of van der Waal's forces

A catalyst:

(1) Increases the average kinetic energy of the reacting molecules

(2) Increases the activation energy

(3) Alters the reaction path mechanism

(4) Increases the frequency of collisions of the reacting species

A catalyst is a substance that:

(1) Increases the equilibrium constant of the reaction

(2) Changes the equilibrium conc. of reaction

(3) Shortens the time to reach equilibrium

(4) Supplies the energy of the reaction

The separation of colloidal particles (or purification of sol) from particles of molecular dimensions is known as:

1. Photolysis

2. Dialysis

3. Pyrolysis

4. Peptization

Lyophilic sols are:

(1) Irreversible sols

(2) They are prepared from inorganic compounds

(3) Not coagulated by adding electrolytes

(4) Self-stabilizing