Which of the following will be most effective in the coagulation of Fe(OH)₃ sol ?

• KCN

• BaCl₂

• NaCl

• Mg₃(PO₄)₂

Tyndall effect shown by colloids is due to :

• scattering of light by the particles

• movements of particles

• reflection of light by the particles

• coagulation of particles

Alum is added to muddy water because :

• it acts as disinfectant

• it results in coagulation of clay and sand

• clay is soluble in alum, hence removes it

• it makes water alkaline, which is good for health

Active charcoal is a good catalyst because :

• made up of carbon atoms

• is very reactive

• has more adsorption power

• has inert nature toward reagent

385.

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