Which one of the following characteristics is not correct for physical adsorption ?

• Adsorption on solids is reversible

• Adsorption increases with increase in temperature

• Adsorption is spontaneous

• Both enthalpy and entropy of adsorption are negative

Size of colloidal particles is in the range :

• 0.05 mµ -0.1 mµ

• 25µ - 30µ

• 0.1 µ- 1mµ

• 10µ - 20µ

Which is more powerful to coagulate the negative colloid?

• ZnSO₄

• Na₃PO₄

• AlCl₃

• K₄[Fe(CN)₆]

Hydrolysis of urea is an example of

• homogenous catalysis

• heterogenous catalysis

• biochemical catalysis

• zeolite catalysis

The velocity of oxidation of oxalic acid by acidified KMnO₄ increases as the reaction progress. It is an example of

• promoters

• catalytic poisons

• autocatalysis

• inhibitors

Which of the following is not a property of colloidal solution?

• Heterogeneity

• Particle size > 100 nm

• Tyndall effect

• Brownian movement

137.

Alloy is an example of

• gel

• solidified emulsion

• solid solution

• sol

Which of the following is an intrinsic colloid ?

• Glue

• Arsenic sulphide

• Gold

• All of these

Coagulation is not done by

• persistant dialysis

• boiling

• electrophoresis

• peptisation

The homogeneous catalysis is shown by

• Haber's process, N₂ + 3H₂ $\stackrel{\mathrm{Fe}}{\to }$ 2NH₃

• Ostwald process, 4NH₃ + 5O₂ $\stackrel{\mathrm{Pt}}{\to }$ 4NO + 6H₂O

• Contact process, 2SO₂ + O₂ $\stackrel{\mathrm{Pt}}{\to }$ 2SO₃

• 2C₂H₅OH $\stackrel{{\mathrm{H}}_2{\mathrm{SO}}_4}{\to }$ C₂H₅-O-C₂H₅ + H₂O