Self Studies
Self Studies
Self Studies
Self Studies

Surface Chemistry Test - 18

Result Self Studies

Surface Chemistry Test - 18
  • Score

    -

    out of -
  • Rank

    -

    out of -
TIME Taken - -
Self Studies

SHARING IS CARING

If our Website helped you a little, then kindly spread our voice using Social Networks. Spread our word to your readers, friends, teachers, students & all those close ones who deserve to know what you know now.

Self Studies Self Studies
Weekly Quiz Competition
  • Question 1
    1 / -0

    Directions For Questions

    Emulsions are also called the colloidal solutions in which the dispersed phase as well as dispersion medium are liquids. It may be oil-in-water or water-in-oil type. Emulsifiers can be used to stabilize the emulsion. Soaps, detergents, proteins and gums are used as emulsifiers.

    ...view full instructions

    Which of the following examples is/are oil-in-water-type emulsion?
    Solution
    Oil in water (o/w) type : In these emulsions, oil forms the dispersed phase and water, the dispersion medium. For example: milk, vanishing cream, etc. They are are also called aqueous emulsions. 

    Water in oil (w/o) type : In these emulsions, water is in the dispersed phase and oil is in the dispersion medium. For example: butter, cold cream etc. They are also called oil emulsions.
  • Question 2
    1 / -0
    Example of an intrinsic colloid is:
    Solution
    Hint: Lyophilic colloids are also called Intrinsic Colloids.

    Correct Answer: Option C

    Explanation:

    Based on the nature of the interaction between the dispersed phase and the dispersion medium:
    Colloids are classified into two categories—lyophilic and lyophobic.
    (a) Colloidal solutions in which the dispersed phase has a great affinity or love for the dispersion medium are termed lyophilic colloids. Such substances have a tendency to pass directly into colloidal solution when brought in contact with the dispersion medium. The lyophilic colloids are also called intrinsic colloids. Egg-albumin is an inherent or essential sol.

    (b) Lyophobic colloids: Substances which when mixed with the dispersion medium do not form the colloidal sol but their sols can be prepared by special methods.
    They are also called extrinsic colloids. Example: Sols of metal sulfides, sols of metallic hydroxides, etc.

    Hence, from the above explanation, we can say that the correct answer is option $$C$$.
  • Question 3
    1 / -0

    Directions For Questions

    Emulsions are also called the colloidal solutions in which the dispersed phase as well as dispersion medium are liquids. It may be oil-in-water or water-in-oil type. Emulsifiers can be used to stabilize the emulsion. Soaps, detergents, proteins and gums are used as emulsifiers.

    ...view full instructions

    Which of the following is homogeneous?
    Solution
    The emulsion is a colloidal system consisting of immiscible liquids. 
    Milk is an example of emulsion in which particles of liquid fat are dispersed in water. In common occurrence, however, one of the liquids is water and the other, and oily substance insoluble in it. The suspended droplets are larger than the particles of the sols. It is because of the density differences between the phases being small.

    Hence, the correct option is $$A$$
  • Question 4
    1 / -0
    The process of passing of a precipitate into colloidal solution on adding an electrolyte is called
    Solution

  • Question 5
    1 / -0
    Sorption is the term used when :
    Solution
    Sorption is the term used when both adsorption and absorption takes place. The substance gets uniformly distributed in the bulk of the solid but at the same time its concentration is higher at the surface than in the bulk.
  • Question 6
    1 / -0
    An emulsifier is an agent which :
    Solution
    Hint: An emulsifier is a substance that stabilises the emulsion by increasing its kinetic stability.

    Correct Answer: $$C$$

    Explanation for correct option :
    First, let us understand what colloids are:
    Colloids are formed by the mixing of the dispersion medium and the dispersed phase which are neither true solutions nor suspensions. The dispersed medium in a colloidal system refers to the medium in which colloidal particles are dispersed while the dispersed phase is the phase dispersed through the medium. Together, dispersed phase and dispersion medium form colloidal systems or colloids.

    Coming to the term ‘emulsion’, we see that:
    In order to prepare stable emulsions, it is important to add a third component known as an emulsifier or emulsifying agent in suitable amounts. Several types of emulsifiers are known:
    (i) Long-chain compounds with polar groups such as soap, sulphonic acid, sulphates, etc.
    (ii) Most of the lyophilic colloids also act as emulsifiers such as glue, gelatin, etc.
    (iii) Certain insoluble powders as clay, lamp black, etc.
    (iv) Soluble substances like iodine also act as emulsifiers.
    Therefore, for the purpose of stabilizing the emulsion, an emulsifying agent or an emulsifier is added to the emulsion. For example, milk is an emulsion with liquid fat as the dispersed phase and liquid water as a dispersion medium and casein is the emulsifier.
    Hence, option $$(C)$$ is the correct option.

  • Question 7
    1 / -0
    An oil-soluble dye is mixed with emulsion and the emulsion remains colourless. Then, it is :
    Solution
    An oil-soluble dye is mixed with emulsion and the emulsion remains colourless. Then, it is oil in water emulsion.
    Oil is the dispersed phase and water is the dispersion medium. Such emulsions are called aqueous emulsions.
  • Question 8
    1 / -0
    Assertion : Physical adsorption of molecules on the surface requires activation energy.
    Reason : The bonds of adsorbed molecules are broken.
    Solution
    No appreciable activation energy is needed for physical adsorption of molecules on the surface. Enthalpy of chemisorption is high as it involves chemical bond formation. No bonds are broken between adsorbed molecules.
    Therefore, both assertion and reason are incorrect.
  • Question 9
    1 / -0
    There is desorption of physical adsorption when :
    Solution
    There is desorption of physical adsorption when temperature is increased.
    The process of removal of an adsorbed substance from the surface on which it is adsorbed is called desorption. It is the reverse of adsorption and can be brought about by heating or by reducing the pressure.
  • Question 10
    1 / -0
    In the adsorption of oxalic acid on activated charcoal, the activated charcoal is called :
    Solution
    Adsorption :
    The phenomenon of attracting and retaining the molecules of a substance on the surface of a liquid or a solid resulting into a higher concentration of the molecules on the surface is called adsorption. 

    Adsorption of a gas by charcoal :
    Finely divided activated charcoal has a tendency to adsorb a number of gases like ammonia, sulphur dioxide, chlorine, phosgene, etc. In this case, charcoal acts as an adsorbent while gas molecules act as adsorbate.

    Adsorption of oxalic acid on activated charcoal:
     The molecules of gases or liquids or the solutes in solutions get adhered to the surface of the solids. In adsorption process two substances are involved. One is the solid or the liquid on which adsorption occurs and it is called adsorbent. The second is the adsorbate, which is the gas or liquid or the solute from a solution which gets adsorbed on the surface.
Self Studies
User
Question Analysis

  • Correct -

  • Wrong -

  • Skipped -

My Perfomance
  • Score

    -

    out of -
  • Rank

    -

    out of -
Re-Attempt Weekly Quiz Competition
Self Studies Get latest Exam Updates
& Study Material Alerts!
No, Thanks
Self Studies
Click on Allow to receive notifications
Allow Notification
Self Studies
Self Studies Self Studies
To enable notifications follow this 2 steps:
  • First Click on Secure Icon Self Studies
  • Second click on the toggle icon
Allow Notification
Get latest Exam Updates & FREE Study Material Alerts!
Self Studies ×
Open Now