Which of the following is true in respect of adsorption?

1

(a)

\(\triangle G<0,\triangle S>0,\triangle H<0\)

(b)

\(\triangle G<0,\triangle S<0,\triangle H<0\)

(c)

\(\triangle G>0,\triangle S>0,\triangle H<0\)

(d)

\(\triangle G<0,\triangle S<0,\triangle H>0\)

Which of the following statements is uncorrect regarding physiosorption?

1

(a)

It occurs because of van der Eaals forces

(b)

More easily liquefiable gases are adsorbed readily

(c)

Under high pressure, it results into multimolecular layer on adsorbent surface

(d)

Enthalpy of adsorption \(\left( \triangle { H }_{ adsorption } \right) \) is low and positive

Which of the following is correct about lyophilic sols?

1

(a)

They are irreversible

(b)

They are formed by inorhanic substances.

(c)

They are readily coagulated by addition of electrolytes.

(d)

They are self-stabilized.

Purple of cassius is a cooloidal sol of

1

(a)

silver

(b)

platinum

(c)

gold

(d)

iron

Which of the following electrolytes will be most effective in the coagulation of gold sol?

1

(a)

NaNO₃

(b)

K₄ [Fe(CN)₆]

(c)

Na₃PO₄

(d)

MgCl₂

How does a delta formed at the meeting place of sea and river water?

1

(a)

Electrolytes present in sea water coagulate colloidal solution of muddy river water forming deltas.

What will be the charge on AgI colloidal particles when it is prepared by addition of small amount of \(AgNO_{ 3 }\) to KI slution in water. What is responsible for development of this charge?

1

(a)

It will be negatively charged due to adsorption of \({ I }^{ - }\) ions as KI is in excess.

What is meant by 'shape-selective catalysis' of reactions?

1

(a)

shape-selective catalysis: The catalysis which depends upon the pore structure of the catalyst and molecular size of reactant and product molecules is called shape-selective catalysis, e.g. Zeolites are shape-selective catalysis due to their honey- comb structure. ZSM-5 (Zeolite Sieve of Molecular porosity is used to convert methanol into gasoline (petrol).

A sol is prepared by addition of excess of \({ AgNO }_{ 3 }\) solution in KI solution. What charge is likely to develope on the colloidal particles?

1

(a)

AgI is likely to have positive charge due to adsorption of \({ Ag }^{ + }\) on surface.

If we add equimolar amount of \(Fe{ \left( OH \right) }_{ 3 }\) to \({ As }_{ 2 }{ S }_{ 3 }\) sol, what will happen?

1

(a)

Mutual coagulation will take place because \(Fe{ \left( OH \right) }_{ 3 }\) is positively charged colloid, whereas \({ As }_{ 2 }{ S }_{ 3 }\) is negatively charged colloid.

Adsorption of a gas on the surface of a solid adsorbent is......................(exothermic or endothermic or neither exothermic nor endothermic).

1

(a)

exothermic

Increasing the adsorbing power of an adsorbent by subdividing it is called...............of the solid adsorbent.

1

(a)

activation

The nature of forces involved in physical adsorption are................... .

1

(a)

van der Waals forces

The heat od adsorption in physisorption lies in the range.............kJ mol^-1.

1

(a)

20-40

Adsorption of N₂ gas on iron at 83 K is........where as at 773 K, it is.....................(fill in the type of adsorption).

1

(a)

physisorption, chemisorption.