WorksheetsSurface chemistry - Review
Total questions: 65
Worksheet time: 49mins
Which of the following interface cannot be obtained?
liquid-liquid
solid-liquid
liquid-gas
gas-gas
Which one is a homogeneous mixture?
Milk dissolved in water
Whipped Cream
Blood dissolved in water
Sodium Hypochlorite dissolved in water
The tyndall effect can be seen in...
Suspension
Solution
Colloids
All of the above
Which has the largest particles?
Solution
Colloids
Suspension
None of the above
Tyndall effect occurs when the colloidal particle ........
adsorbs the light
passes the light
scatters the light
is able to do brownian motion
Electrolyte excess in a colloidal system can be removed by ......... process
Electrophoresis
Ultrafiltration
Dialysis
Peptization
Which substance that includes in aerosol system?
soap foam
paint
colored glass
smoke
Colloid preparation from molecules or ions to form colloidal particles is called .......
coagulation
condensation
Mechanical dispersion
Peptization
Which one is the example of colloidal system when solid is dispersed in gas?
fog
foam
smoke
pumice stone
Coconut oil is non polar, while water is polar. They can not be mixed and will not dissolve each other.
Emulsion is produce when oil-water mixture is shaken and is added by....
hot water
salt solution
soap solution
kerosene
These are colloidal system that the dispersed phase is liquid, except...
milk
soap foam
margarine
fog
Identify the property of colloid related to Tyndall effect.
Mechanical property
Colligative property
Optical property
Electrical property
The purpose of an emulsifier is to ___________ .
Decrease surface area in a suspension
Reduce the interfacial tension between immiscible phase
Minimize the size of globules
Improve medication taste
A substance that allows oil and water to mix or emulsify is known as ________ .
Antioxidant
Emulsifier/Surfactant
Preservative
Colouring agent
The tail of a surfactant molecule is oil-loving or known as ________?
hydrophile
lipophobic
lipophilic
hydrophilic
At high concentration of soap in water, soap behaves as ____________.
molecular colloid
associated colloid
macromolecular colloid
lyophilic colloid
Freshly prepared precipitate sometimes gets converted to colloidal solution by ___________.
coagulation
electrolysis
diffusion
peptisation
Which of the following electrolytes will have maximum coagulating value for AgI/Ag+ sol?
Na2S
Na3PO4
Na2SO4
NaCl
The values of colligative properties of colloidal solution are of small order in comparison to those shown by true solutions of same concentration because of colloidal particles __________________.
exhibit enormous surface area.
remain suspended in the dispersion medium.
form lyophilic colloids.
are comparatively less in number.
Which of the following process is not responsible for the presence of electric charge on the sol particles?
Electron capture by sol particles.
Adsorption of ionic species from solution.
Formation of Helmholtz electrical double layer.
Absorption of ionic species from solution
gold sol is -------- colloid
lyophobic
lyophilic
associated
At the equilibrium position in the process of adsorption ___________.
ΔH > 0
ΔH = TΔS
ΔH > TΔS
ΔH < TΔS
What is the process in which colloid will coagulate due to the opposite charge presence?
Tyndall effect
Brownian motion
Electrophoresis
Dialysis
In physisorption adsorbent does not show specificity for any particular gas because ______________.
involved van der Waals forces are universal.
gases involved behave like ideal gases.
enthalpy of adsorption is low.
it is a reversible process.
Bredig's arc method is used for the preparation of colloidal soln of:
Metal like silver, gold, etc
Organic compounds
Two liquids
Inorganic compounds
'Greater the valency, the higher is the ciagulating power of ion'. This rule was introduced by
Hardy Schulz
Maxwell
Hardy Lewis
Faraday
Temperature above which micelles formation takes place is called as
Critical temperature
Kraft temperature
Freezing point
None of these
Select the FALSE statement about adsorption.
The value of adsorption enthalpy of physical adsorption is less than chemical adsorption.
Physical adsorption occurs due to Van der Waals'forces.
Chemical adsorption decreases at high temperature and low pressure.
Physical adsorption is reversible.
Recognize the method in preparing lyophilic sol.
Chemical reduction
Peptization
Mechanical dispersion
Direct mixing of the solid with the liquid
Select the CORRECT statement regarding adsorption process.
A substance is encapsulated in the solid or liquid form.
A substance is distributed throughout the solid or liquid form.
A substance becomes attached to the surface of a solid or a liquid.
It may involve chemisorption only.
" A substance is first ground to coarse particles and then mixed with the dispersion medium to produce a suspension."
Name the method to produce sol as mentioned above.
Double decomposition
Mechanical dispersion
Bredig's arc
Peptization
Select the CORRECT property of a lyophobic sol.
The colloidal particles are not easily detected by the ultra microscope.
The surface tension of dispersed phase is generally lower than that of the dispersion medium.
The viscosity of a sol is similar to that of the dispersion medium (solvent).
Addition of low concentration of electrolytes has little effect on the coagulation.
Define adsorbate.
The removal of adsorbed particles.
A solid material on which adsorption occurs.
A substance in the adsorbed phase.
The study on the interaction phenomena on the surface.
Choose the CORRECT assumptions of the Langmuir isotherm.
Answers can be more than one options.
The solid surface of adsorbent is uniform (all the adsorption sites are equivalent. Every side have same energy (homogeneous surface).
All adsorption occurs through same mechanism.
A maximum of a monolayer (one adsorbate molecule per site) can be adsorbed. Adsorption cannot proceed above monolayer coverage.
Adsorbed molecule do not interact; adsorption is localized (immobile)
Adsorption can proceed multilayer coverage.
Entropy during adsorption ...........
Decreases
Increases
Remain Same
Cannot say
Which of the following ion will have highest coagulating power for coagulating a negatively charged sol?
NaCl
CaCl2
AlCl3
KCl
The movement of colloidal particles towards the oppositely charged electrodes on passing electric current is known as
Tyndall Effect
Brownian Motion
Electrophoresis
Coagulation
The process of settling of colloidal particle is called....
Peptization
Caogulation
Dialysis
Emulsification
It is a process of removing a dissolved substance from a colloidal solution by means of diffusion through a suitable membrane
Electrophoresis
Dialysis
Precipitation
Peptization
Which is not true for chemisorption?
It involves high activation energy
It is highly specific
It involves chemical bond formation
It is reversible
In gas masks which substance is used to absorb toxic gases and vapours?
Coal powder
Animal charcoal
Wood charcoal
Activated charcoal
The amount of heat evolved when one mole of a gas is adsorbed on a solid surface is called as
Molar enthalpy of absorption
Molar enthalpy of desorption
Molar enthalpy of adsorption
entropy of adsorption
When the concentration of adsorbate is more on the surface than the bulk of the adsorbent it is called as
Positive adsorption
Negative adsorption
Positive absorption
Negative absorption
If x is amount of adsorbate and m is the amount of adsorbent, which of the following relations is not related to adsorption process?
x/m = f(p) at constant T
x/m = f(p) at constant T
p = f(T) at constant (x/m)
x/m = p × T
Which plot is the adsorption isobar for chemisorption x is the amount of gas adsorbed on the mass m at temperature T at constant pressure?
Which gas is adsorbed strongly be charcoal
CO
N2
H2
O2
Chemisorption is
multimolecular nature
reversible
often highly specific and directional
not specific
Rate of physisorption increases with temperature
decrease in temperature
increase in temperature
decrease in pressure
decrease in surface area
The volume of gases H2, CH4, CO2 and NH3 adsorbed by 1 gm charcoal at 293 K can be given in the order?
CH4 > CO2 > NH3 > H2
CO2 > NH3 > H2 > CH4
NH3 > CO2 > H2 > CH4
NH3 > CO2 > CH4 > H2
Which of the following statements is incorrect regarding physisorption?
It occurs because of van der Walls forces
More easily liquefiable gases are adsorbed readily
Under high pressure it results into multimolecular layer on adsorbent surface
Enthalpy of adsorption (ΔHadsorption) is low and positive
A plot of log x/m versus log p for the adsorption of a gas on a solid gives a straight line with slope equal to
n
1/n
log K
- log K
Example for physisorption
adsorption of O2 on tungsten
adsorption of H2 on nickel
adsorption of N2 on mica
adsorption of C2H5OH on nickel
which of the following is /are true for the adsorption of H2O and NH3 on the surface of zeolite?
it involves mainly vanderwaal's force of attraction
it involves mainly electrostatic force of attraction
high heat of adsorption
low heat of adsorption
adsorption is specific in nature
Which one of the following is an example of adsorption?
ammonia in contact with water
ammonia in contact with hydrogen gas
silica gel in contact with water vapors
None of above
In Freundlich Adsorption isotherm, the value of 1/n is
1 in case of physical adsorption
1 in case of chemical adsorption
Between 0 and 1 in all cases
Less than 0 all cases
The Langmuir adsorption isotherm is deduced using the assumption
The adsorbed molecules interact with each other
The adsorption takes place in multilayers
The adsorption sites are equivalent in their ability to adsorb the particles
The heat of adsorption varies with coverage
In Langmuir's model of adsorption of a gas on a solid surface
the adsorption at a single site on the surface may involve multiple molecules at the same time
the mass of gas striking a given area of surface is proportional to the pressure of the gas
the mass of gas striking a given area of surface is independent of the pressure of the gas
the rate of dissociation of adsorbed molecules from the surface does not depend on the surface covered
Glutamine has two pKa (2.17 and 9.13). Which one is the major form of glutamine at pH = 1.5?
Which of the following are true for isoelectric focusing?
proteins separate according to their isoelectric point
proteins stop migrating at the isoelectric point
All the proteins move from Anode to Cathode
no further procedure is necessary to separate the proteins
Assertion : A gas with higher critical temperature gets adsorbed to more extent than a gas with lower critical temperature.
Reason : The easily liquifiable gases get adsorbed to more extent.
assertion is true but the reason is false
assertion is false but the reason in true.
both assertion and reason are true and the reason is a correct explanation of assertion
If both assertion and reason are true but reason is not a correct explanation of assertion.
Which of the following is an example of cationic detergent?
Alkyltrimethyl ammonium chloride
Sodium salts of alkyl sulphates
Sodium salts of alkyl benzene sulphonic acids
Polyethers
Micelles behave as colloids only when?
Concentration is less than CMC
Concentration is equal to CMC
Concentration is greater than CMC
They always behave as colloids
Sodium laurel Sarcosinate is an example of____
Anionic surfactants
Cationic surfactants
Non-ionic surfactants
Zwitter ionic surfactants
.Most micelles are spherical and contain between_____surfactant monomers
0-50
50-100
150-200
1500-2000
Select the incorrect statement from the following options.
In the micelle formation, the water soluble heads are directed towards the centre
In the micelle formation, the water soluble heads are on the surface in contact with the water
In the micelle formation, the water insoluble tails are directed towards the centre
None of the mentioned
