SURFACE CHEMISTRY Quiz-2

SURFACE CHEMISTRY QUIZ-2

Dear Readers,

IIT JEE exam which consists of JEE Main and JEE Advanced is one of the most important entrance exams for engineering aspirants. The exam is held for candidates who are aspiring to pursue a career in the field of engineering and technical studies. Chemistry is important because everything you do is chemistry! Even your body is made of chemicals. Chemical reactions occur when you breathe, eat, or just sit there reading. All matter is made of chemicals, so the importance of chemistry is that it's the study of everything..

Q1. Among the electrolytes Na2SO4,CaCl2,Al2(SO4)3 and NH4Cl, the most effective coagulation agent for Sb2S3 sol is

•  Na2SO4
•  CaCl2
•  Al2 (SO4)3
•  NH4Cl

Solution
(c). Sb2S3 is an anionic sol, therefore cation of highest valency (Al^(3+)in the present case would be most effective coagulating agent.

Q2.Catalyst used in polymerization of ethene is:

•  TiCl4 and AlR3
•  Fe, Co
•  H3 PO4
•  Zeolites

Solution
(b). For polymerization of ethene, Fe and Co is used

Q3.  The process of removing dissolved impurities from a colloidal system by means of diffusion through suitable membrane under the influence of an electric field is called

•   Electro-osmosis
•  Electrodialysis
•  Electrophoresis
•  Peptization

Solution
(b). Dialysis is a process of purifying a substance

Q4. Softening of hard water is done using sodium aluminium silicate (zeolite). This causes

•  Adsorption of Ca^(2+) and Mg^(2+) ions of hard water replacing Na^⨁ ions
•  Adsorption of Ca^(2+) and Mg^(2+) ions of hard water replacing Al^(3+) ions
•  Both true
•  None is true

Solution
(a). Hardness of water is due to carbonate or sulphate of Ca^(2+) and Mg^(2+) ions. When sodium aluminium silicate is added Na^⨁ replaces Ca^(2+) and Mg^(2+) by adsorption, and hence water become soft

Q5.Lyophilic sols are

•  Irreversible sols
•  They are prepared from inorganic compounds
•  Coagulated by adding electrolytes
•  Self-stabilising

Solution
 (d). Lyophilic sols are self stabilizing because these sols are reversible and are highly hydrated in the solution

Q6. Soaking of water by a sponge is an example of

•  Simple adsorption
•  Physical adsorption
• Chemisorption
•  Absorption

Solution
(d). Soaking of water by a sponge is adsorption because water also accumulates in bulk of sponge as well as on the surface of it

Q7.Which is not the correct statement for a catalyst?

•  a) It does not alter E_a
•  The surface of a catalyst adsorbs reactants
•  Catalyst may form intermediates with reactants
•  Action of enzyme catalyst is always specific

Solution
(a). Catalyst changes the activation energy(Ea)

Q8.Which one of the following statements is wrong about adsorption?

•  It is a selective and specific process
•  It is a reversible process
•  An increase in the gaseous adsorbate causes an increase in a adsorption. However, at high pressure, the adsorption becomes constant
•  It is an endothermic process

Solution
(d). Adsorption is an exothermic process

Q9.Micelles are

•  Ideal solution
•  Associated colloids
•  Adsorbed surfaces
•  Absorbent solutes

Solution
option-(c)

Q10. Smoke has generally blue tinge. It is due to

•  Scattering
•  Coagulation
•  Brownian motion
• Electro-osmosis

Solution
(a). Due to scattering, smoke has blue tinge