JEE Questions for Chemistry Surface Chemistry Quiz 5 - MCQExams.com

Pick out the statement which is not relevant in the discussion of colloids.
  • Sodium aluminium silicate is used in the softening of hard water
  • Potash alum is used in shaving rounds and as a styptic in medicine
  • Artificial rain is caused by throwing electrified sand on the clouds from an aeroplane
  • Deltas are formed at a place where the river pours its water into the sea
In the hydrogenation of oils, the catalyst used is
  • Iron
  • Platinum
  • Nickel
  • Molybdenum
Gold number gives
  • The amount of gold present in the colloid
  • The amount of gold required to break the colloid
  • The amount of gold required to protect the colloid
  • None of the above
Which requires catalyst?

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  • 2)
    Chemistry-Surface Chemistry-8362.png

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  • All
A catalyst in a reaction
  • Increases the activation energy of the forward reaction
  • Increases the activation energy of the backward reaction
  • Increases the activation energy of both the reactions
  • Decreases the activation energy of both the reactions
A catalyst in a reaction changes which of the following?
  • Equilibrium constant
  • Entropy
  • Rate constant
  • Nature of products
A liquid which markedly scatters a beam of light (visible in a dark room) but leaves no residue when passed through a filter paper is best described as
  • A suspension
  • A true solution
  • Lyophobic sol
  • Lyophilic sol
Which one of the following substances adsorbs hydrogen gas most strongly?
  • Activated carbon
  • Silica gel
  • Platinum black
  • Iron powder
Most effective electrolyte causing coagulation of a negatively charged As2S3 sol is
  • MgCl2
  • KCl
  • K3Fe(CN)6
  • Na2SO4
Swimming for a long time in salt water makes the skin of one’s finger tips wrinkled. Which one of the following properties is responsible for this observation?
  • Osmosis
  • Dialysis
  • Electrodialysis
  • Coagulation
Peptization is a process of
  • Precipitation of colloidal particles
  • Purification of colloids
  • Dispersing precipitate into colloidal sols
  • Movement of colloidal particles in the electrical field
As2S3 sol. is
  • Positive colloid
  • Negative colloid
  • Neutral colloid
  • None of the above
Sulphur sol contains
  • Discrete Sulphur atoms
  • Discrete Sulphur molecules
  • Large aggregates of Sulphur molecules
  • Water dispersed in solid Sulphur
Cow milk is an example of natural emulsion stabilized by
  • Fat
  • Water
  • Casein
  • Mg++ ions
The colour of the colloidal particles of gold obtained by different methods differ because of
  • Variable valency of gold
  • Different concentration of gold particles
  • Different types of impurities
  • Different diameters of colloidal particles
Which one of the following statements regarding catalysis is not true?
  • A catalyst remains unchanged at the end of the reaction
  • A catalyst can initiate a reaction
  • A catalyst does not alter the equilibrium in a reversible reaction
  • Catalysts are sometimes very specific in terms of reactions
Crystalloids differ from colloids mainly in respect of
  • Electrical behavior
  • Particle size
  • Particle nature
  • Solubility
A colloidal solution is subjected to an electrical field. The particles move towards anode. The coagulation of same sol is studied using NaCl, BaCl2 and AlCl3 solutions. Their coagulating power should be
  • NaCl > BaCl2 > AlCl3
  • BaCl2 > AlCl3 > NaCl
  • AlCl3 > BaCl2 > NaCl
  • BaCl2 > NaCl > AlCl3
For adsorption of a gas on a solid, the plot of log x/m vs log P is linear with slope equal to (n being whole number)
  • k
  • Log k
  • n
  • 1/n
Peptization denotes
  • Digestion of food
  • Hydrolysis of proteins
  • Breaking and dispersion into the colloidal state
  • Precipitation of solid from colloidal dispersion
Which of the following statements about a catalyst is/are true?
  • A catalyst accelerates the reaction by bringing down the free energy of activation
  • A catalyst does not take part in the reaction mechanism
  • A catalyst makes the reaction more feasible by making the ΔGo more negative
  • A catalyst makes the equilibrium constant of the reaction more favorable for the forward reaction
Brownian movement is found in
  • Colloidal solution
  • Suspension
  • Saturated solution
  • Unsaturated solution
Random motion of colloidal particles is known as
  • Dialysis
  • Brownian movement
  • Electroosmosis
  • Tyndall effect
In physical adsorption, gas molecules are bound on the solid surface by
  • Chemical forces
  • Electrostatic forces
  • Gravitational forces
  • Van der Waal’s forces
Milk can be preserved by adding a few drops of
  • Formic acid solution
  • Formaldehyde solution
  • Acetic acid solution
  • Acetaldehyde solution
The Rubin number which was proposed by Ostwald as an alternative to the Gold number in order to measure the protective efficiency of a lyophillic colloid may be defined as the
  • Mass in milligrams of a colloid per 100 c.c. of solution which just prevents the colour change of standard sol of dye Congo-Rubin from red to violet when 0.16 g eq. KCl is added to it
  • Mass in grams of a colloid per 100 c.c. of solution which just prevents the colour change of standard sol of dye Congo-Rubin from red to violet when 0.1 M KCl is added to it
  • Mass in grams of a colloid per 100 c.c. of solution which just prevents the colour change of standard sol of dye Congo-Rubin from red to violet when 0.2 M KCl is added to it
  • Mass in grams of a colloid per 100 c.c. of solution which just prevents the colour-change of standard sol of dye Congo-Rubin from red to violet when 1 M KCl is added to it
Cod Liver oil is
  • Fat dispersed in water
  • Water dispersed in fat
  • Water dispersed in oil
  • Fat dispersed in fat
Which of the following kind of catalysis can be explained by the adsorption theory?
  • Homogeneous catalysis
  • Acid-base catalysis
  • Heterogeneous catalysis
  • Enzyme catalysis
Which one of the following will have the highest coagulating power for a ferric hydroxide sol.?
  • NaCl
  • BaCl2
  • K2CrO4
  • K3[Fe(CN)6]
At CMC the surfactant molecules
  • Decompose
  • Become completely soluble
  • Associate
  • Dissociate
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