For coagulating As₂S₃ colloidal solution which of the following will have the lowest coagulation value?

• NaCl

• KCl

• BaCl₂

• AlCl₃

Which of the following chemical reactions is homogeneous catalytic reaction?

• N₂(g) + 3H₂(g) $\stackrel{\mathrm{Fe}}{\to }$ 2NH₃(g)

• 2SO₂(g) + O₂(g) $\stackrel{\mathrm{NO}}{\to }$ 2SO₃ (g)

• CO(g) + 3H₂(g) _{$\stackrel{\mathrm{Ni}}{\to }$} CH₄(g) + H₂O (g)

• 2SO₂(g) + O₂(g) $\stackrel{{\mathrm{V}}_2{\mathrm{O}}_5}{\to } 2{\mathrm{SO}}_3\left(\mathrm{g}\right)$

According to the adsorption theory of catalysis the speed of the reaction increase because

• the concentration of reactant molecules at the active centres of the catalyst becomes high due to adsorption

• in the process of adsorption, the activation energy of the molecules becomes large

• absorption produces heat which increases the speed of the reaction

• adsorption lowers the activation energy of the reaction

Which of the following will have the highest coagulating power for As₂S₃ colloid?

• PO${}_4^{3-}$

• SO${}_4^{2-}$

• Al³⁺

• Na⁺

325.

Adsorption is multilayer in the case of

• physical adsorption

• chemisorption

• Both (a) and (b)

• None of the above

Which of the following is not a method of preparation of colloidal solution?

• Electrical dispersion

• Peptization

• Coagulation

• Mechanical dispersion

Consider the following statements. The role of catalyst is to

(1) reduce the activation energy

(2) increase the activation energy

(3) increase the rate of attainment of equilibrium

(4) decrease the rate of attainment of equilibrium

Which ofthe statements given above are correct?

• (2) and (4)

• (1) and (4)

• (1) and (3)

• (2) and (3)

Finely divided powder of charcoal adsorbs the substance X to a large extent. This is because

• the surface area of charcoal is increased

• charcoal powder can be spread over X homogeneously

• X can be spread over charcoal homogeneously

• charcoal is highly reactive

Which one of the following has minimum gold number?

• Starch

• Sodium oleate

• Gelatin

• Gum arabic

Syneresis is a process in which

• spontaneous outcome of internal liquid without disturbing gel structure takes place

• sol particles absorb light

• aggregation of molecules to form micelle

• separation of soluble impurities from sols take place