JEE Questions for Chemistry Surface Chemistry Quiz 4 - MCQExams.com

Negatively charged colloidal solution of clay in water will need for precipitation the minimum amount of
  • aluminium sulphate
  • potassium sulphate
  • sodium hydroxide
  • hydrochloric acid
Which one of the following does not involve coagulation?
  • Formation of delta regions
  • Peptization
  • Treatment of drinking water by potash alum
  • Clotting of blood by the use of ferric chloride
Which of the following has maximum coagulation power with ferric hydroxide sol ?
  • Cryolite
  • K2C2O4
  • K3 [Fe(CN)]6
  • K4[Fe(CN)6]
Which of the following electrolytes is least effective in coagulating ferric hydroxide solution?
  • KBr
  • K2 SO4
  • K2CrO4
  • K4[Fe(CN)6]
Which is the wrong pair?
1. Starch solution : sol
II. Aq. NaCl : true solution
III. milk : emulsion
IV. Aq. BaSO4 : true solution
  • Only I
  • Only III
  • Only IV
  • Only II
Mention the type of reaction to obtain Au (sol).
Reaction, 2AuCl3 + 3HCHO + 3H2O → 2Au(sol) + 3HCOOH + 6HCl
  • Hydrolysis
  • Oxidation
  • Reduction
  • Double decomposition
Which one of the following impurities present in colloidal solution cannot be remove by electrodialysis?
  • Sodium chloride
  • Potassium sulphate
  • Urea
  • Calcium chloride
  • Magnesium chloride
Which one of the following is correctly matched?
  • Emulsion-Curd
  • Foam-mist
  • Aerosol-smok
  • Solid sol-cake
Among the following, the surfactant that will form micelles in aqueous solution at the lowest molar concentration at ambient conditions, is
  • CH3(CH2)15 N+(CH3)3 Br-
  • CH3(CH2)11OSO-3 Na+
  • CH3(CH2)6COO- Na+
  • CH3(CH2)11 N+(CH3)3 Br-
Gold numbers of protective colloids A, B, C and D are 0.50, 0.01, 0.10 and 0.005, respectively. The correct order of their protective powers is
  • D < A < C < B
  • C < B < D < A
  • A < C < B < D
  • B < D < A < C
Bleeding due to a cut can be stopped by applying ferric chloride solution in the laboratory. This is due to
  • coagulation of negatively charged blood particles by Fe3+ ions
  • coagulation of positively charged blood particles by Cl - ions
  • reaction taking place between ferric ions and the haemoglobin forming a complex
  • common element, iron, in both FeCl3 and haemoglobin
Peptisation denotes
  • hydrolysis of proteins
  • digestion of food
  • breaking and dispersion into colloidal state
  • precipitation of solid from colloidal dispersion
The phenomenon observed when a beam of light is passed through a colloidal solution is
  • cataphoresis
  • dielectrophoresis
  • coagulation
  • Tyndall effect
When a sulphur sol is evaporated sulphur is obtained. On mixing with water sulphur sol is not formed. The sol is
  • lyophilic
  • reversible
  • hydrophobic
  • hydrophilic
On adding 1 mL of solution of 10% NaCl to 10mL of gold sol in the presence of 0.25 g of starch, the coagulation is just prevented. The gold number of starch is
  • 0.25
  • 0.025
  • 2.5
  • 25
  • 250
The disperse phase, dispersion medium and nature of colloidal solution (lyophilic or lyophobic) of 'gold sol' respectively are
  • solid, solid, lyophobic
  • liquid, liquid, lyophobic
  • solid, liquid, lyophobic
  • solid, liquid, lyophilic
Tyndall effect shown by colloids is due to
  • scattering of light by the particles
  • movement of particles
  • reflection of light by the particles
  • coagulation of particles
Lyophilic sols are
  • irreversible sols
  • they are prepared from inorganic compounds
  • coagulated by adding electrolytes
  • self-stabilising
The volume of a colloidal particle, VC as compared to the volume of a solute particle in a true solution VS , could be

  • Chemistry-Surface Chemistry-8342.png
  • 2)
    Chemistry-Surface Chemistry-8343.png

  • Chemistry-Surface Chemistry-8344.png

  • Chemistry-Surface Chemistry-8345.png
The disperse phase in colloidal iron (III) hydroxide and colloidal gold is positively and negatively charged, respectively. Which of the following statements is not correct ?
  • Coagulation in both sols can be brought about by electrophoresis
  • Mixing the sols has no effect
  • Sodium sulphate solution causes coagulation in both sols
  • Magnesium chloride solution coagulates the gold sol more readily than the iron (III) hydroxide sol
The concentration of electrolyte required to coagulate a given amount of As2 S3 sol is minimum in the case of
  • magnesium nitrate
  • potassium nitrate
  • potassium sulphate
  • aluminium nitrate
Assertion (A) van der Waals' forces are responsible for chemisorption.
Reason (R) High temperature is favourable for chemisorption.
The correct answer is
  • A is incorrect but R is correct
  • Both A and R are correct and R is the correct explanation of A
  • Both A and R are correct and R is not the correct explanation of A
  • A is correct but R is incorrect
The given graph/data I, II, III and IV represent general trends observed for different physisorption and chemisorption processes under mild conditions of temperature and pressure. Which of the following choice(s) about I, II, III and IV is (are) correct?
Chemistry-Surface Chemistry-8347.png
  • I is physisorption and II is chemisorption
  • I is physisorption and III is chemisorption
  • IV is chemisorption and I is chemisorption
  • IV is chemisorption and III is chemisorption
Choose the correct reason(s) for the stability of the lyohobic colloidal particles.
  • Preferential adsorption of ions from the solution
  • Preferential adsorption of solvent on their surface from the solution
  • Attraction between different particles having opposite charges on their surface
  • Potential difference between the fixed layer and the diffused layer of opposite charges around the colloidal particles
Freundlich equation for adsorption of gases (in amount of x g ) on a solid (in amount of m g ) at constant temperature can be expressed as

  • Chemistry-Surface Chemistry-8348.png
  • 2)
    Chemistry-Surface Chemistry-8349.png

  • Chemistry-Surface Chemistry-8350.png

  • Chemistry-Surface Chemistry-8351.png
If (x/m) is the mass of adsorbate adsorbed per unit mass of adsorbent. p is the pressure of the adsorbate gas and a and b are constants, which of the following represents Langmuir adsorption isotherm ?

  • Chemistry-Surface Chemistry-8353.png
  • 2)
    Chemistry-Surface Chemistry-8354.png

  • Chemistry-Surface Chemistry-8355.png

  • Chemistry-Surface Chemistry-8356.png

  • Chemistry-Surface Chemistry-8357.png
Assertion (A) Catalyst increases the rate of a reaction.
Reason (R) In presence of a catalyst, the activation energy of the reaction increases.
The correct answer is
  • Both A and R are correct and R is the correct explanation of A
  • Both A and R are correct but R is not the correct explanation of A
  • A is correct but R is incorrect
  • Assertion is not correct, but Reason is correct
In a reversible reaction, the catalyst
  • increases the activation energy of the backward reaction
  • increases the activation energy of the forward reaction
  • decreases the activation energy of both forward and backward reaction
  • decreases the activation energy of forward reaction
Select wrong statement.
  • If a very small amount of AlCl3 is added to gold sol, coagulation occurs, but if a large quantity of AlCl3 is added, there is no coagulation.
  • Organic ions are more strongly adsorbed on charged surfaces in comparison to inorganic ions.
  • Both emulsifier and peptising agents stabilised colloids but their actions are different.
  • Colloidal solutions are thermodynamically stable.
The gold numbers of some colloidal solutions are given below.
Chemistry-Surface Chemistry-8359.png
  • C > B > A
  • A > B > C
  • A = B = C
  • B > A > C
0:0:1


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