Explain what is observed
(i) when a beam of light is passed through a colloidal sol.
(ii) an electrolyte, NaCl is added to hydrated ferric oxide sol.
(iii) electric current is passed through a colloidal sol?
Answer:
The catalytic reaction that depends upon the pore structure of the catalytic and te size of the reactant and the sizes of the reactant and product molecule is called shap-selective catalysis.
Zeolites are microporous complex silicates in which some of silicon atoms are replaced by Al3+ ions. These are sodium aluminum silicates or calcium aluminum silicates. Their general formula is Mx/m [(AlO2)x (SiO2)y] m H2O where, n is valency of metal cation, Mn+ These are found in nature as such and are also synthesised in laboratory.
The characteristic features are:
(i) These are shape-selective catalyst or can act as molecular sieves.
(ii) These have honey-comb like structure.
(iii) These have specific pore-size lying between 260 to 740 pm.