The correct statement regarding changes in the catalyst during a reaction is -

a.  Physical

b.  Qualitative

c.  Chemical

d.  Quantitative

1. (a, b)
2. (b, c)
3. (c, d)
4. (a, d)

Physical adsorption of a gaseous species may change to chemical adsorption with ..........

1.  Decrease in temperature.

2.  Increase in temperature.

3.  Increase in surface area of adsorbent.

4.  Decrease in surface area of adsorbent.

In physisorption adsorbent does not show specificity for any particular gas because..........

1.  Involved van der Waals’ forces are universal.

2.  Gases involved behave like ideal gases.

3.  Enthalpy of adsorption is low.

4.  It is a reversible process.

Among the following options the example of absorption is :

1.  Water on silica gel.

2.  Water on calcium chloride.

3.  Hydrogen on finely divided nickel.

4.  Oxygen on metal surface.

On the basis of the data given below, the gas which shows the least adsorption on a definite amount of charcoal is-

1. CO₂
2. SO₂
3. CH₄
4. H₂

In which of the following reactions heterogeneous catalysis is involved ? 

$\left(i\right) 2S{O}_2\left(g\right)+O_2\left(g\right)\stackrel{NO\left(g\right)}{\to }2S{O}_3\left(g\right)$

$\left(ii\right) 2S{O}_2\left(g\right)\stackrel{Pt\left(s\right)}{\to }2S{O}_3\left(g\right)$
$\left(iii\right) N_2\left(g\right)+ 3 H_2\left(g\right) \stackrel{Fe\left(s\right)}{\to }2N{H}_2\left(g\right)$
$\left(iv\right) C{H}_{3}COOC{H}_3\left(l\right)+H_{2}O\left(l\right)\stackrel{CH\left(l\right)}{\to }$
$C{H}_{3}COOCH\left(aq\right)+C{H}_{3}OH\left(aq\right)$

1.  (ii), (iii)

2.  (ii), (iii) and (iv)

3.  (i), (ii) and (iii)

4.  (iv)

At high concentration of soap in water, soap behaves as .......

1. Molecular colloid.

2. Associated colloid.

3. Macromolecular colloid.

4.  Lyophilic colloid.

Tyndall effect is shown by 

Method by which lyophobic sol can be protected.

1.  By addition of oppositely charged sol.

2.  By addition of an electrolyte.

3.  By addition of lyophilic sol.

4.  By boiling.

Freshly prepared precipitate sometimes gets converted to colloidal solution by ......

1.  Coagulation

2.  Electrolysis

3.  Diffusion

4.  Peptisation