Surface Chemistry Worksheet





The study of chemical reaction during interface is called surface chemistry. Surface chemistry deals with Adsorption, absorption, catalyst, Colloidal state and others.

Here, you can find questions related to “Surface Chemistry” and their answers:

Questions:

1. Which of the following is an example of a solid aerosol?

(a)    Volcanic dust

(b)   Ammonium chloride fumes

(c)    Cloud

(d)   Smoke

 

2. The isoelectric point of a colloidally dispered material is the pH value at which:

(a)    The dispersed phase has pH value equal to 7.0

(b)   The dispersed phase does not migrate in an electric-field

(c)    The dispersed phase has pH value equal to zero

(d)   The dispersed phase migrates in an electric field

 

3. Oxides, metallic hydroxides and basic dyestuffs are all examples of:

(a)    Negative sols

(b)   Neutral sols

(c)    Positive sols

(d)   None of these

 

4. A jelly is formed when a gelatinous material separates:

(a)    Slowly and uniformly

(b)   Very fast and nonuniformly

(c)    Slowly and nonuniformly

(d)   Very fast

 

5. which of the following gases is adsorbed most by activated charcoal?

(a)    Cl_2

(b)   CO_2

(c)    O_2

(d)   N_2

 

6. Zero-order reactions are found in:

(a)    Heterogeneous catalytic reactions

(b)   Catalysed reactions

(c)    Homogeneous catalytic reactions

(d)   None of these

 

7. Spontaneous adsorption of a gas on a solid surface is an exothermic process because:

(a)    \Delta S for the gas increases

(b)   \Delta G for the gas increases

(c)    \Delta S for the gas decreases

(d)   \Delta Hfor the system increases

 

8. Molecular crystals are subdivide into:

(a)    Metallic crystals and alloys

(b)   Covalent and nonmetallic networks

(c)    Van der wall’s crystals and hydrogen-bonded ‘ crystals

(d)   Ionic crystals and polymers

 

9. SiO_2 belongs to the:

(a)    tetragonal system

(b)   rhombohedral system

(c)    hexagonal system

(d)   orthorhombic system

 

10. On the basis of its unit-cell structure, NaHCO_3 belongs to the:

(a)    Tetragonal

(b)   Monoclinic system

(c)    Tericlinic system

(d)   Cubic system

 

11. for b.c.c. lattice, d_{110} : d_{100} : d_{111} in the ration:

(a)    1 :  1 : 154

(b)   1 : 1.414 : 0.577

(c)    1 : 1.414 : 1.54

(d)   1: 0.557 : 1.414

 

12. Cubic close-packing of equal-sized described by:

(a)    ABAC AC AB ..

(b)   ABC ACB ABC ACB….

(c)    AB AB AB AB….

(d)   ABC ABC ABC….

 

13. The point defect found in CaF_2 is called:

(a)    Edge-dislocation defect

(b)   Schottky defect

(c)    Frenkel defect involving anions

(d)   Frenkel defect involving cations

 

14. In the reaction, KMnO_4 + H_2SO_4 + H_2C_2O_4 \to Mn^{++} ion, acts as:

(a)    Negative catalyst

(b)   Enzyme catalyst

(c)    Auto-catalyst

(d)   Positive catalyst

 

15. When KCIO_3 is heated, it decomposes into KCl and O_2. If some MnO_2 is added, the reaction goes much faster because:

(a)    Better contact is provided by MnO_2

(b)   MnO_2  decomposes to give O_2

(c)    MnO_2 provides heat by reacting

(d)   MnO_2 acts as a catalyst

 

16. The activity of catalyst may be increased by:

(a)    Cooling

(b)   Adding in a suitable solvent

(c)    Powdering

(d)   Heating

 

17. An example of an autocatalytic reaction is:

(a)    Hydrogenation of vegetable oils using nickel catalyst

(b)   The decomposition of nitroglycerine

(c)    Breakdown of _6C^{14}

(d)   Thermal decomposition of KCIO_3 + MnO_2 mixture

 

18. Choose the correct statement from the following?

(a)    A catalyst speeds up forward reactions and slows the backward reaction

(b)   A catalyst is active only in solution

(c)    The composition of equilibrium mixture is not changed by a catalyst

(d)   The addition of catalyst changes equilibrium constant ( )

 

19. A lyophilic colloid is more stable than a lyophobic one, since:

(a)    the particle size in the former is greater than that of the latter

(b)   the particles in the former are surrounded by solvent molecules

(c)    the former has much affinity for the dispersion medium

(d)   the particles in the former are stabilized by charge as well as solvent layer around the particles

 

20. Which is the correct statement in case of milk?

(a)    Milk is an emulsion of fat in water

(b)   Milk is stabilised by fat

(c)    Milk is an emulsion of protein in water

(d)   Milk is stabilised by protein

 

21. Point out incorrect statement:

(a)    Langmuir adsorption assumes that equilibrium is reached when rate of adsorption is equal to the rate of desorption

(b)   At high pressures, the Freundlich isotherm assumes the form \dfrac{x}{m} \propto P

(c)    Adsorption involves accumulation of liquid or gas on the surface of a solid

(d)   Physisorption involves the formation of multi molecular layers

 

22. The nature of bonding forces in the adsorption are:

(a)    Purely chemical

(b)   Purely physical such as van der Wall’s forces

(c)    Both chemical and physical

(d)   Sometimes physical and sometimes chemical

 

23. Cottrell precipitator works on the principle of:

(a)    Addition of electrolytes

(b)   Neutralization of change on colloids

(c)    Distribution law

(d)   Le-chatelier’s principle

 

24. When a colloidal solution is observed under ultramicroscope we can see:

(a)    Light scattered by colloidal particle

(b)   Shape of the colloidal particle

(c)    Relative size of the colloidal particle

(d)   Size of the colloidal particle

 

25. Given below are a few electrolytes, indicate which one among them will bring about the coagulation of a gold sol quickest and in the least of concentration:

(a)    MgSO_4

(b)   K_4[Fe(CN)_6]

(c)    AlCl_3

(d)   NaCl

Answers:

1.(c)           2. (d)        3. (b)         4. (a)       5. (a)

6. (c)         7. (d)        8. (a)          9. (a)       10. (c)

11. (a)        12. (a)      13. (d)        14. (c)      15. (c)

16. (b)       17. (d)       18. (a)       19. (b)      20. (d)

21. (b)       22. (c)       23. (a)       24. (c)     25. (a)



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