NEET Chemistry Chapter Wise Mock Test – Surface Chemistry
Adsorbed acetic acid on activated charcoal is
Which of the following is not applicable to the phenomenon of adsorption?
(a) ΔH >0
50 mL of 1 M oxalic acid (molar mass = 126) is shaken with 0.5 g of wood charcoal. The final concentration of the solution after adsorption is 0.5 M. What is the amount of oxalic acid adsorbed per gram of carbon?
At the equilibrium position in the process of acfeorption
(a) ΔH >0
Adsorption in multilayer occurs in case of
(a) physical adsorption
(b) chemical adsorption
(c) Both (a) and (b)
(d) None of the above
Which one of the following characteristics is not correct for physical adsorption?
(a) Adsorption on solids is reversible
(b) Adsorption increases with increase in temperature
(c) Adsorption is spontaneous
(d) Both enthalpy and entropy of adsorption are negative
The heats of adsorption in physisorption lies in range (in kJ/mol)
(a) 40 – 400
(c) 200 – 400
Adsorption due to strong chemical force is called
(c) reversible adsorption
(d) Any of the above
Plot of log x/m against log p is a straight line inclined at an angle of 45°. When the pressure is 0.5 atm and Freundlich parameter k is 10, the amount of solute adsorbed per gram of adsorbent will be (log 5 = 0.6990)
(a) 1 g
(b) 2 g
(c) 3 g
(d) 5 g
The Langmuir adsorption isotherm ia deduced using the assumption
(a) the adsorption takes place is monolayer
(b) the adsorption sites are equivalent in their ability to adsorb the particles
(c) the heat of adsorption varies with coverage
(d) the adsorbed molecules interact with each other
Which one of the following is an example for homogeneous catalysis?
(a) Manufacture of sulphuric acid by contact process
(b) Manufacture of ammonia by Haber’s process
(c) Hydrolysis of sucrose in presence of dilute hydrochloric acid
(d) Hydrogenation of oil
Which of the following process does not occur at the interface of phases?
(b) Heterogeneous catalysis
(c) Homogeneous catalysis
According to the adsorption theory of catalysis, the speed of reaction increases because
(a) adsorption lowers the activation energy of the reaction
(b) the concentration of reactant molecules at the active centres of the catalyst becomes high due to adsorption
(c) in the process of adsorption, the activation energy of the molecules becomes large
(d) adsorption produces heat which increases the speed of the reaction
The efficiency of enzyme catalysis is due to its capacity to
(a) form a strong enzyme-substrate complex
(b) change the shape of the substrate
(c) lower the activation energy of the reaction
(d) form a colloidal solution in water
The enzyme which can catalyse the conversion of glucose to ethanol is
Colloidal solution of gold prepared by different methods are of different colours because of
(a) variable valency of gold
(b) different concentrations of gold particles
(c) impurities produced by different methpds
(d) different diameters of colloidal gold particles
When HgS is passed through nitric acid, the product is
(a) rhombic (S)
(b) prismatic (S)
(c) monclinic (S)
(d) amorphous (S)
Cellulose dispersed in ethanol is called
(d) hydrophilic sol
Bredig’s arc method cannot be used to prepare colloidal solution of which of the following?
The density of gold is 19 g/cm3. If 1.9x 10-4. g of gold is dispersed in 1 L of water to give a sol having spherical gold particles of radius 10 nm, then the number of gold particles per mm3.of the sol will be
(a) 1.9x 1012
(c) 6.3 x 1010
(d) 2.4 x 106
At high concentration of soap in water, soap behaves as
(a) nrftifecular colloid
(b) associated colloid
(c) macro molecular colloid
(d) lisophilic colloid
Which one of the following forms micelles in aqueous solution above certain concentration?
(b) Dodecyl trimethyl ammonium chloride
(c) Pyridinium chloride
Which of the following forms cationic micelles above certain concentrations?
(ap£bdium ethyl sulphate
(b) Sodium acetate
(d) Cetyltrimethyl ammonium bromide
Lyophilic colloids are stable due to
(a) charge on particles
(b) large size of the particle
(c) small size of the particles
(d) layer of dispersion medium on the particles
Which of the following process is responsible for the formation of delta at a place where rivers meet the sea?
(b) Colloid formation
Tyndall effect is more pronounced in
(a) hydrophilic sols
(b) hydrophobic sols
(c) lyophilic sols
(d) Both (a) and (b)
Blood may be purified by
Which of the following electrolytes is least effective in coagulating ferric hydroxide solution?
Milk can be preserved by adding a few drops of
(a) formic acid solution
(b) formaldehyde solution
(c) acetic acid solution
(d) acetaldehyde solution
The concentration of electrolyte required to coagulate a given amount of As2S3 sol is minimum in case of
Which is more powerful to coagulate the negative colloid?
The coagulation values of AICI3 and NaCI are 0.093 and 52 respectively. The ratio of coagulating power of both will be
(a) 0.093 : 1
(b) 52 : 1
(c) 559 : 1
(d) 1.788 : 1
Alum helps in purifying water by
(a) forming Si complex with dirt particles
(b) sulphate part which combines with dirt and removes it
(c) making mud water soluble
(d) aluminium ions which coagulates the mud particle
Bleeding due to a cut can be stopped by applying ferric chloride solution in the laboratory. This is due to
(a) coagulation of negatively charged blood particles by Fe3+ ions
(b) coagulation of positively charged blood particles by Cl– ions
(c) reaction taking place between ferric ions and the haemoglobin forming a complex
(d) common element, iron, in both FeCI3 and haemoglobin
On adding 1 ml of solution of 10% NaCI to 10 mL of gold sol in the presence of 0.25 g of starch, the coagulation is just prevented. The gold number of starch is
(a) fat dispersed in water
(b) fat dispersed in milk
(c) fat dispersed in fat
(d) water dispersed in milk
Which of the following substances will precipitate the negatively charged emulsions? [NCERT Exemplar] I. KCI II. glucose III. urea IV. NaCI
The correct answer is
(a) I and II
(b) I and III
(c) I and IV
(d) II and III
An emulsion cannot be broken by and
II.adding more amount of dispersion medium
IV.adding emulsifying agent The correct answer is
(a) I and II
(b) II and III
(c) II and IV
(d) I, II and III
Direction (Q. Nos. 43-44) In the following questions, more than one of the answers given may be correct. Select the answers and mark it according to the codes.
(a) 1,2 and 3 are correct
(b) 1 and 2 are correct
(c) 2 and 4 are correct
(d) 1 and 3 are correct
Which among the following statements are correct with respect to adsorption of gases on a solid?
1. The extent of adsorption is equal to kpn according to Freundlich isotherm.
2. The extent of adsorption is equal to kp1/n according to Freundlich isotherm.
3. The extent of adsorption is equal to (1 + bp)/ap according to Langmuir isotherm.
4. The extent of adsorption is equal to ap/(1 + bp) according to Langmuir isotherm.
Which of the following statements are true for hydrophilic solution?
1. They do not require electrolytes for stability.
2. Their coagulation is irreversible.
3. Their surface tension is usually lower than that of dispersion medium.
4. Their viscosity is of the order of that of water.
Direction (Q. Nos. 47-51) Each of these questions contains two statements: Assertion and Reason. Each of these questions also has four alternative choices, only one of which is the correct answer. You have to select one of the codes (a), (b), (c) and (d) given below.
(a) Assertion is true, Reason is true; Reason is a correct explanation for Assertion
(b) Assertion is true, Reason is true; Reason is not a correct explanation for Assertion
(c) Assertion is true, Reason is false
(d) Assertion is false, Reason is true
Assertion An emulsion becomes stable if soap is added to it.
Reason Soap contains both hydrophilic and hydrophobic parts.
Assertion The activity of a catalyst depends upon the strength of physisorption.
Reason The reactant must adsorb very strongly for the catalyst to be active.
Assertion Aqueous gold colloidal solution is red in colour.
Reason The colour arises due to scattering of light by colloidal gold particles.
Assertion A catalyst increases the rate of a reaction.
Reason In presence of a catalyst, the activation energy of the reaction decreases.
Assertion In chemisorption, adsorption keeps on increasing with temperature
Reason Heat keeps on providing more and more activation energy.
Which property of colloidal solution is independent of charge on the colloidal particles?
(d) Tyndall effect
In Freundlich adsorption isotherm, the value of 1/n is
(a) between 0 and 1 in all cases
(b) between 2 and 4 in all cases
(c) 1 in case of physical adsorption
(d) 1 in case of chemisorption
The protecting power of lyophilic colloidal sol is expressed in terms of
(a) coagulation value
(b) gold number
(c) critical micelle concentration
(d) oxidation number
The gold numbers of some colloidal solutions are given below.
The protective nature of these colloidal solutions follow the
(a) C >B >A
(b) A >B >C
(c) A = B = C
(d) B >A >C
Purple of cassius is a/an
(a) colloidal sol of gold
(b) colloidal sol of silver
(c) colloidal sol of platinum
(d) oxyacid of gold
The simplest way to check whether a system is colloidal is
(b) finding out particle size
(c) Tyndall effect
(d) Brownian movement
Which of the following is not correct?
(a) Milk is a naturally occurring emulsion
(b) Gold sol is a lyophilic sol
(c) Physical adsorption decreases with rise in temperature
(d) Chemical adsorption is unilayered
The Brownian motion is due to
(a) temperature fluctuation within the liquid phase
(b) attraction and repulsion between charges on the colloidal particles
(c) impact of the molecules of the dispersion
(d) convectional currents
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