Question

Which of the following can absorb the largest volume of hydrogen gas?
A. Finely divided platinum
B. Finely divided nickel
C. Colloidal solution of palladium
D. Colloidal Hydroxide

Answer 1

Hint: We need to know what is adsorption and what are the factors that favour it. We need to remember that the adsorption is a surface phenomenon where atoms, molecules or species are accumulated on the surface of another substance. For example gases like hydrogen and oxygen get adsorbed on the surface of activated charcoal. Here oxygen and hydrogen are known as the adsorbate and the activated charcoal is known as the adsorbent.

Complete step by step answer:
The given questions demand us to analyse the adsorption where the adsorbate is hydrogen gas and the adsorbents are solids. Hence we need to study the adsorption of a gas on a solid.
The factors on which the extent of adsorption of a gas on solid depends are:
1.Nature of the gas
3.2.Nature of the solid
4.Surface area of the solid
5.Pressure of the gas
6.Temperature of the gas
The given options include finely divided substances and colloidal solutions. We know that colloids have a higher surface area as compared to finely divided substances. Hence Finely divided platinum and nickel cannot adsorb more than colloidal solutions. In addition, colloids usually have large surface areas for a given volume and are therefore excellent at adsorption. Palladium colloid is the best in absorbing hydrogen gas due to its larger surface area as compared to colloidal hydroxide.

Hence, the correct option is option C.

Note: We must be noted that the function of catalysts also depends on the surface area of the catalyst which is the adsorbent. Greater is the surface area of the catalyst, larger will be the room provided for the reactants to form the products. Palladium is therefore widely used as an excellent catalyst for chemical reactions involving hydrogen and oxygen.