470+ Engineering Chemistry Solved MCQs

1.

Hardness of water is due to the presence of salts of                          

A. potassium
B. chlorine
C. magnesium
D. boron
Answer» C. magnesium
Explanation: hardness of water is due to the presence of salts of calcium and magnesium. hard drinking water may have moderate health benefits, but can pose serious problems in industrial settings, where water hardness is monitored to avoid costly breakdowns in boilers, cooling towers, and other equipment that handles water.
2.

Select the incorrect statement from the following option.

A. water which does not form lather with soap and forms white scum is called hard water
B. hard water contains dissolved calcium and magnesium salts in it
C. in hard water, cleansing quality of soap is depressed
D. due to the presence of dissolved hardness- producing salts, the boiling point of water is depressed
Answer» D. due to the presence of dissolved hardness- producing salts, the boiling point of water is depressed
Explanation: due to the presence of dissolved hardness-producing salts, the boiling point of water is elevated. elevation in boiling point is one of the most important colligative property. all the other options are correct.
3.

Select the incorrect statement from the following option.

A. the taste of hard water is better than soft water
B. the dissolved calcium in hard water can help to produce strong teeth
C. hard water coats the lead piping with a layer of insoluble calcium carbonate which prevents poisonous lead dissolving in water
D. boiler feed water should also be hard in nature
Answer» D. boiler feed water should also be hard in nature
Explanation: boiler feed water should be free from hardness otherwise explosion may occur. all the other options are correct. the taste of hard water is better than soft water and dissolved calcium in hard water can help to produce strong teeth. hard water coats the
4.

Which of the following is not a unit of hardness?

A. parts per million
B. degree centigrade
C. degree clarke
D. degree french
Answer» B. degree centigrade
Explanation: degree centigrade is not a unit of hardness. degree centigrade is the unit of temperature. the unit for hardness is ppm (parts per million), degree clarke and degree french. all these three units are inter-related.
5.

Hardness of water is conventionally expressed in terms of equivalent amount of

A. h2co3
B. mgco3
C. caco3
D. na2 co3
Answer» C. caco3
Explanation: hardness of water is conventionally expressed in terms of equivalent amount of caco3. the total water hardness is the sum of the molar concentrations of ca2+ and mg2+, in mol/l or mmol/l units.
6.

The chemical equivalent of MgSO4 salt is

A. 10,000
B. 30,000
C. 50,000
D. 70,000
Answer» D. 70,000
Explanation: 1 degree clarke = 1 part of caco3 per 70,000 parts of water. it is calculated mathematically.
7.

1 ppm =

A. 0.07 0fr
B. 0.70fr
C. 0.10fr
D. 0.010fr
Answer» C. 0.10fr
Explanation: 1 ppm = 0.10fr. it is calculated mathematically.
8.

How many grams of MgCO3 dissolved per litre gives 84 ppm hardness?

A. 70.56 mg/l
B. 48.23 mg/l
C. 81.49mg/l
D. 66.12 mg/l
Answer» A. 70.56 mg/l
Explanation: 70.56 mg/l of mgco3 dissolved per litre gives 84 ppm hardness.
9.

EDTA method for hardness determination is a less accurate and inconvenient procedure.

A. true
B. false
Answer» B. false
Explanation: edta method for hardness determination is a more accurate, convenient and rapid procedure. ethylene diaminetetraacetic acid (edta), is an amino poly-carboxylic acid and a colorless, water- soluble solid.
10.

Estimation of hardness can be determined by                  types.

A. 2
B. 3
C. 4
D. 5
Answer» A. 2
Explanation: estimation of hardness can be determined by two types. they are soap titration method and edta method.
11.

Total hardness of water can be determined by titrating the fixed volume of water against the standard                        solution.

A. soap
B. alkaline soap
C. acidic soap
D. alcoholic soap
Answer» D. alcoholic soap
Explanation: total hardness of water can be determined by titrating the fixed volume of water against the standard alcoholic soap solution.
12.

The sodium soap will precipitate all the hardness causing ions into their respective

A. carbonates
B. bicarbonates
C. stereates
D. chlorides
Answer» C. stereates
Explanation: the sodium soap will precipitate all the hardness causing ions into their respective stereates in the beginning of the soap titration method.
13.

The water which form lather directly with the soap is called                      

A. hard water
B. soft water
C. partially hard water
D. very hard water
Answer» B. soft water
Explanation: the water which forms lather directly with the soap is called soft water. the water which forms precipitates when reacted with soap is called as the hard water.
14.

EDTA method is also called as                    

A. complexometric titration
B. complex titration
C. complement titration
D. complexion titration
Answer» A. complexometric titration
Explanation: edta method is also called as the complexometric titration. in edta method is ethylene diamine tetra acetate is the compound used to remove the hardness.
15.

The indicator used in the EDTA method is

A. benzene
B. phenopthalene
C. ethylene diamine
D. erichrome black t
Answer» D. erichrome black t
Explanation: the indicator used in the edta method is erichrome black t. the hardness causing ions like ca++ and mg++ forms the unstable complexes with reacting the erichrome black t.
16.

The change in colour is sharper at the PH of                  

A. 5
B. 10
C. 15
D. 20
Answer» B. 10
Explanation: the change in the colour of the ions is sharper at the ph of the 10 than that of the other ranges of the ph.
17.

At PH=10, the metal dye complex has the colour                  

A. wine red
B. blue
C. green
D. pink
Answer» A. wine red
Explanation: at the ph=10, the metal dye complex ion has the colour is wine red but the dye itself has the blue colour at the ph of 10.
18.

To prepare EDTA solution                     grams of EDTA is dissolved in the one litre of water.

A. 1
B. 2
C. 3
D. 4
Answer» D. 4
Explanation: to prepare edta solution, four grams of the edta is dissolved in the one litre of the water. this is the standard edta solution used to determine the hardness of water.
19.

                   drops of indicator is used in the EDTA method.

A. 1 to 2 drops
B. 2 to 3 drops
C. 2 to 4 drops
D. 5 to 8 drops
Answer» A. 1 to 2 drops
Explanation: 1 to 2 drops of the indicator is used in the edta method. 0.5gms of the dye is dissolved into the 100ml of alcohol and the indicator of two to three drops is added.
20.

The buffer used in the EDTA solution must have the PH of                        

A. 20
B. 15
C. 10
D. 5
Answer» C. 10
Explanation: the buffer used in the edta solution must have the ph of 10. freshly prepared solutions are more affective to have the accurate results.
21.

The standard hard water is prepared such that each ml must contain                  mg of CaCO3.

A. 1
B. 2
C. 3
D. 4
Answer» A. 1
Explanation: the 1g of pure caco3 is dissolved in the minimum amount of concentrated hcl diluted to 1ltr of distilled water such that it contains 1mg of caco3.
22.

Water is mainly used in boilers for the generation of                                  

A. power
B. electricity
C. steam
D. current
Answer» C. steam
Explanation: water is mainly used in boilers for the generation of steam. this steam is further used in the power plants for the generation of electricity.
23.

Which of the following is not a result of the excess of impurity in boiler-feed?

A. scale and sludge formation
B. decomposition
C. corrosion, priming and foaming
D. caustic embrittlement
Answer» B. decomposition
Explanation: excess of impurities in boiler- feed results in scale and sludge formation, corrosion, priming, foaming and caustic embrittlement. it does not contribute to the decomposition process.
24.

The scales decrease the efficiency of boiler and chances of explosions are also there.

A. true
B. false
Answer» A. true
Explanation: the scales decrease the efficiency of boiler and chances of explosions are also there. scale is the precipitate that is hard and adhering on the inner wall.
25.

Foaming is caused by the formation of

A. acids
B. alcohols
C. oils and alkalis
D. ketones
Answer» C. oils and alkalis
Explanation: foaming is caused by the formation of oils and alkalis. oils and alkalis becomes sticky and greasy on the surface and hence results in foaming.
26.

Corrosion is the decay or disintegration of boiler body material either due to chemical or electrochemical reaction with environment.

A. true
B. false
Answer» A. true
Explanation: corrosion is the decay or disintegration of boiler body material either due to chemical or electrochemical reaction with environment. it converts a refined metal to a more stable form, such as its oxide, hydroxide, or sulphide.
27.

Ion exchange process is also called as

A. permutit’s process
B. demineralization
C. zeolite process
D. lime soda process
Answer» B. demineralization
Explanation: ion exchange process is also called as the demineralization. the zeolite process is otherwise called as the ion exchange process.
28.

The operational cost of the ion exchange process is                      

A. high
B. low
C. very high
D. very low
Answer» B. low
Explanation: the capital cost of the ion exchange process is very high. the operational cost of the ion exchange process is about low.
29.

The hardness in the ion exchange process is reduced to                        

A. 0-1ppm
B. 0-2ppm
C. 0-3ppm
D. 0-4ppm
Answer» B. 0-2ppm
Explanation: the hardness of the ion exchange process is reduced to 0 to 2ppm. it
30.

The total                      are removed completely in the ion exchange process.

A. dissolved gases
B. dissolved solids
C. dissolved solvents
D. dissolved other impurities
Answer» B. dissolved solids
Explanation: the total dissolved solids are removed completely in the ion exchange process. in lime soda process, the total dissolved solids are reduced only.
31.

In ion exchange process, the iron and manganese ions are removed from the water.

A. true
B. false
Answer» A. true
Explanation: in ion exchange process, not only iron and manganese ions are removed from the water but also all the cations are removed.
32.

Water softened during                      method will be ideal in boilers.

A. zeolite method
B. lime soda method
C. demineralisation method
D. permutit’s process
Answer» B. lime soda method
Explanation: water softened during the demineralisation method is completely free from all the impurities and flaws. so, the water after the softening by this method will be ideal for boilers.
33.

The regeneration of acids and alkalis in ion exchange process is                      

A. cheaper
B. costlier
C. time taking
D. hard process
Answer» B. costlier
Explanation: the one of the disadvantages of the ion exchange process is the regeneration of the acids and alkalis in ion exchange process is costlier.
34.

In ion exchange process, the cation exchange resin is generated by passing

A. acids
B. dilute acids
C. alkalis
D. dilute alkalis
Answer» B. dilute acids
Explanation: in ion exchange process, the cation exchange resin is generated by passing the dilute acids. the anion exchange resin is generated by passing alkali.
35.

In the case of the zeolites, ion exchange process do not function properly because of the                      

A. turbidity
B. suspended matter
C. turbidity and suspended matter
D. neither turbidity nor suspended matter
Answer» C. turbidity and suspended matter
Explanation: in case of zeolites, ion exchange process do not function properly because of the turbidity and suspended matter as they send to cover the surface of the resin.
36.

The initial equipment in the ion exchange process is                        

A. more
B. less
C. very less
D. very high
Answer» A. more
Explanation: the initial equipment in the ion exchange process is more. continuous supply of softened water can be made available by providing storage facilities.
37.

The residual hardness after the treatment of water is about                      

A. 1 ppm
B. less than 1ppm
C. 2 ppm
D. less than 2pmm
Answer» D. less than 2pmm
Explanation: the residual hardness after the treatment of the water is about less than 2ppm. so, they are suitable for the high pressure boilers.
38.

The continuous supply of soft water can be provided by having                          

A. storage facilities
B. required amount of ppm
C. high pressure boilers
D. 1ppm
Answer» A. storage facilities
Explanation: the continuous supply of soft water can be provided by having storage facilities and also two columns of each resin.
39.

The cost of the resins used in the ion exchange process is                    

A. high
B. low
C. moderate
D. depends on water
Answer» A. high
Explanation: the cost of the resins used in the ion exchange process is high and the regeneration of the resins in also a costly process.
40.

The mineral free water is not used in

A. pharmaceuticals
B. cosmetics
C. explosives
D. drinking
Answer» D. drinking
Explanation: in drinking water some minerals must be present. in pharmaceuticals, cosmetics, explosives and in other manufacturing processes, the mineral free water is used.
41.

In which process of water softening, ion exchange phenomenon takes place?

A. lime soda process
B. zeolite process
C. boiling
D. demineralization process
Answer» B. zeolite process
Explanation: in the zeolite process, calcium and magnesium are removed from hard water by ion exchange phenomenon.
42.

In which process of water softening, the chemicals are added to remove hardness from water?

A. lime soda process
B. zeolite process
C. boiling
D. demineralization process
Answer» A. lime soda process
Explanation: in the lime soda process, lime and soda are added to remove temporary and permanent hardness from water.
43.

Zeolites are complex compound of

A. aluminium and lime
B. silica and soda
C. aluminium, silica and soda
D. lime and soda
Answer» C. aluminium, silica and soda
Explanation: zeolites are complex compound of aluminium, silica and soda. it has the property of removing calcium and magnesium from water and substituting sodium in their place.
44.

The color of the artificial zeolite permutit is                          

A. grey
B. yellow
C. green
D. white
Answer» D. white
Explanation: the artificial zeolite permutit has a large and lustrous grain. they are white in color and has an appearance of coarse sand.
45.

Natural zeolite is mainly processed from

A. white sand
B. green sand
C. grey sand
D. red sand
Answer» B. green sand
Explanation: the natural zeolite is mainly processed from green sand, which is also called as glauconite. it has lesser exchange value than artificial zeolite.
46.

The color of the natural zeolite is

A. green
B. grey
C. black
D. blue
Answer» A. green
Explanation: the color of the natural zeolite is green as it is processed from glauconite which is green in color. it has an exchange value of 6500-9000gm of hardness per m3 of zeolite.
47.

The chemical formula of Permutit is

A. sioal2o3na2o
B. sio2al2o3na2o
C. sio2al2o3nao
D. sio3al2o3na2o
Answer» B. sio2al2o3na2o
Explanation: the chemical formula of permutit is sio2al2o3na2o. the increase in the value of sio2 increases its resistance to aggressive attacks.
48.

The zeolite process is unsuitable for water containing iron and manganese.

A. true
B. false
Answer» A. true
Explanation: iron and manganese bearing water deposit hydroxides on the surface of zeolite or react with zeolite to substitute iron and manganese for sodium, which is an irreversible reaction. this makes the zeolite process unsuitable.
49.

The thickness of the layers of filter sand of zeolite softener is                          

A. 20cm
B. 30cm
C. 40cm
D. 100cm
Answer» D. 100cm
Explanation: the thickness of the layers of filter sand of zeolite softener lies in the range of 75 to 150cm and their functioning is similar to the rapid sand filter.
50.

Salt cannot be separated from brackish water by freezing.

A. true
B. false
Answer» B. false
Explanation: salt can be separated from brackish water by freezing.
51.

Electrodialysis is based on the fact that the ions present in saline water migrate towards their respective electrodes under the influence of applied                        

A. current
B. resistance
C. conductance
D. emf
Answer» D. emf
Explanation: electrodialysis is based on the fact that the ions present in saline water migrate towards their respective electrodes under the influence of applied emf. the potential difference generated between the elctrodes is the main cause of flow of electrons.
52.

The cation selective membrane is embedded with functional groups of

A. positive charge
B. negative charge
C. both positive as well as negative charge
D. neutral
Answer» B. negative charge
Explanation: the cation selective membrane is embedded with functional groups of negative charge as it attracts only positive charges towards them.
53.

Electrodialysis is an electrically driven separation conducted at a very low pressure- driven, size-exclusion filtering process.

A. true
B. false
Answer» A. true
Explanation: electrodialysis is an electrically driven separation conducted at a very low pressure-driven, size-exclusion filtering process. electrodialysis is used to transport salt ions from one solution through ion- exchange membranes to another solution under the influence of an applied electric potential difference.
54.

The ion-exchange membrane are electrically conductive and are not permeable to                        flow, even under pressure.

A. electron
B. oil
C. fluorine
D. water
Answer» D. water
Explanation: the ion-exchange membrane are electrically conductive and impermeable to water flow, even under pressure. electrons can easily flow through these membranes.
55.

Select the incorrect statement from the following option.

A. electrodialysis reversal (edr) was introduced in the commercial sector to improve electrodialysis process
B. the edr process and conventional ed unit operates on the same principle, except at intervals of several times an hour
C. the reversal feature is useful in breaking up films, scales and other deposits
D. electrodialysis process is not economical as per capital cost
Answer» D. electrodialysis process is not economical as per capital cost
Explanation: electrodialysis process is economical as per capital cost and operational expenses are concerned. all the other options are correct.
56.

Which one of the following is not a cation exchanger?

A. amberlite
B. triolite
C. dowex
D. duolite
Answer» B. triolite
Explanation: triolite is not a cation exchanger. amberlite, dowex and duolite are some of the examples of the cation exchanger.
57.

The                  the salt rejection, the better the system is performing.

A. higher
B. lower
C. moderate
D. poor
Answer» A. higher
Explanation: the higher the salt rejection, the better the system is performing. a low salt rejection can mean that the membranes require cleaning or replacement.
58.

What is the osmotic pressure for sea water?

A. 1.5 mpa
B. 1.8 mpa
C. 2.3 mpa
D. 2.45 mpa
Answer» D. 2.45 mpa
Explanation: the osmotic pressure of sea water is 2.45 mpa. the concentration of salt in sea water is 32000-35000 mg/l. the applied pressure on the ro equipment is 5.6- 6.
59.

Membrane permeation rate increases proportionally to effective pressure.

A. true
B. false
Answer» A. true
Explanation: although membrane permeation rate increases proportionally to effective pressure, the highest recommended applied pressure of commercial membranes presently available is 7.0 mpa.
60.

RO membranes are made of                

A. plastic
B. cotton
C. silk
D. polymer
Answer» D. polymer
Explanation: the highest recommended applied pressure of commercial membranes presently available is 7.0 mpa; beyond which compaction will start to occur due to the fact that ro membranes are made of polymers.
61.

Concentrated seawater which is called

A. permeate
B. brine
C. ro water
D. salt water
Answer» B. brine
Explanation: when fresh water is separated from seawater, concentrated seawater which is called brine and is retained on the surface of the ro membrane.
62.

7 REVERSE OSMOSIS.

A. true
B. false
Answer» A. true
Explanation: the salt concentration and the osmotic pressure of the brine are related proportionally, i.e., the osmotic pressure of the brine increases as the salt concentration increases.
63.

The upper limit of brine concentration is

A. 1.5
B. 2
C. 2.5
D. 3
Answer» C. 2.5
Explanation: the upper limit of the brine concentration is usually fixed. the upper limit is normally 1.6-2.5 times that of the normal seawater.
64.

What is the maximum acceptable limit of temperature for RO?

A. 20˚c
B. 30˚c
C. 40˚c
D. 50˚c
Answer» C. 40˚c
Explanation: in order to reduce the effects of temperature to a minimum, the acceptable
65.

What is the design temperature of RO systems?

A. 20˚c
B. 25˚c
C. 30˚c
D. 35˚c
Answer» B. 25˚c
Explanation: ro systems are usually designed to operate at 25°c and water flux falls by 20–25 percent when water temperature is lowered by 10°c.
66.

What is the thumb rule to consider for osmotic pressure?

A. 1 psi for every 86 ppm of na
B. 2 psi for every 86ppm of na
C. 1 psi for every 43 ppm of na
D. 2 psi for every 43 ppm of na
Answer» A. 1 psi for every 86 ppm of na
Explanation: the tendency of a pure solution constituting low solute concentration to flow into solution constituting higher solute concentration is known as osmosis. when pressure greater than osmotic pressure is applied then reverse osmosis takes place. the thumb rule for the consideration of osmotic pressure is 1 psi for every 86 ppm of na.
67.

What is the flux considered while designing a reverse osmosis system for treating RO permeate?

A. 30-40 lmh
B. 12-18 lmh
C. 20-25 lmh
D. 25-30 lmh
Answer» A. 30-40 lmh
Explanation: flux is the amount of water flowing through a particular area. this is dependent both on the nature of water and the membrane surface area. the flux considered for ro permeate is 30-40 lmh.
68.

What is the flux considered while designing a reverse osmosis system for treating bore well water?

A. 30-40 lmh
B. 40-50 lmh
C. 20-30 lmh
D. 12-18 lmh
Answer» C. 20-30 lmh
Explanation: the flux increases with increase in pressure. it also increases with increase in temperature. in case of bore well water, the flux considered is 20-30 lmh.
69.

What is the flux considered while designing a reverse osmosis system for treating surface water?

A. 15-22 lmh
B. 22-30 lmh
C. 12-15 lmh
D. 30-35 lmh
Answer» A. 15-22 lmh
Explanation: the flux to be considered depends on the nature of the water to be treated. the flux is used to determine the number of membranes required for the treatment system. in the case of treating surface water by a conventional method the flux to be considered is 15-22 lmh.
70.

What is the flux considered while designing a reverse osmosis system for treating surface water with UF system?

A. 15-20 lmh
B. 20-30 lmh
C. 12-15 lmh
D. 30-35 lmh
Answer» B. 20-30 lmh
Explanation: the flux to treat surface water by a conventional method and to treat by uf differs. conventional method includes dual media filters. in case the surface water is treated by conventional, the flux considered should be around 20-30 lmh.
71.

What do you mean by the term “Sorption”?

A. attachment
B. detachment
C. diffusion
D. thermal expansion
Answer» A. attachment
Explanation: sorption is a physical and chemical process by which one substance becomes attached to another. the reverse of sorption is desorption.
72.

The desorption curve is higher than the adsorption curve.

A. true
B. false
Answer» A. true
Explanation: theoretically, desorption curve is higher than adsorption curve in low pressure area if the material is mesoporous (2-50nm). if the material is microporous (<2nm), both curves should be matched together.
73.

Which of the following isotherm is applicable to physical adsorption?

A. langmuir
B. bet
C. freundlich
D. kisluik
Answer» C. freundlich
Explanation: the freundlich isotherm was the first isotherm model proposed for sorption processes. it can be applied for non ideal sorption on heterogeneous surfaces, as well as, multilayer sorption. a variation in the slope between 0 and 1 is associated with a chemisorption process, which is more heterogeneous as the value gets closer to 0.
74.

Which type of isotherm is given from the figure, Choose from the following options?

A. type 1 adsorption isotherm
B. type 2 adsorption isotherm
C. type 3 adsorption isotherm
D. type 4 adsorption isotherm
Answer» A. type 1 adsorption isotherm
Explanation: the above graph depicts monolayer adsorption. this graph can be easily explained using langmuir adsorption isotherm. examples of type-i adsorption are adsorption of nitrogen (n2) or hydrogen (h) on charcoal at temperature near to -1800c.
75.

Which of the following statements regarding the physical adsorption of a gas on surface of solid is not correct?

A. on increasing temperature, adsorption increases continuously
B. enthalpy changes are negative
C. adsorption is specific
D. it is reversible in nature
Answer» A. on increasing temperature, adsorption increases continuously
Explanation: physisorption is exothermic in nature. therefore according to le chateliars principle, it occurs readily at low temperature and decreases with increase in temperature.
76.

Which of the following is not characteristic of chemisorption?

A. it is irreversible
B. it is specific
C. it is multilayer phenomenon
D. heat of adsorption is about 400kj
Answer» C. it is multilayer phenomenon
Explanation: chemisorption involves formation of chemical bonds between adsorbate and adsorbent molecules. once the valency is satisfied, the adsorbent molecules can’t form bond with more adsorbate molecules. thus only one layer is formed.
77.

For an adsorbant-adsorbate system obeying the Langmuir adsorption isotherm, b = 0.48 bar-1 and p = 0.16 bar-1. At what pressure will 50% of the surface be covered?

A. 0.05 bar
B. 0.07 bar
C. 0.08 bar
D. 0.04 bar
Answer» B. 0.07 bar
Explanation: given data b = 0.48 bar-1
78.

Adsorption of methane follows the Langmuir adsorption isotherm at 90K. If p = 1.896cm3g-1bar-1 and b = 0.146bar-1. Calculate the value of θ.

A. 0.116 bar
B. 0.514 bar
C. 0.214 bar
D. 0.216 bar
Answer» D. 0.216 bar
Explanation: given data p = 1.896cm3g-1 bar-1
79.

In Langmuir’s model of adsorption of a gas on a solid surface the mass of gas striking a given area of surface is                             to the pressure of the gas.

A. proportional
B. anti proportional
C. independent
D. none of the mentioned
Answer» A. proportional
Explanation: in langmuir’s model of adsorption of a gas on a solid surface the mass of gas striking a given area of surface is proportional to the pressure of the gas.
80.

The physical process that occurs when gas or liquid molecules are brought into contact with a solid surface and condense on the surface

A. absorption
B. adsorption
C. both adsorption and absorption
D. none of the mentioned
Answer» B. adsorption
Explanation: adsorption is the physical process that occurs when gas or liquid molecules are brought into contact with a solid surface and condense on the surface.
81.

Adsorption when interaction between the solid and the condensed molecules is relatively strong as contrasted with physical adsorption.

A. absorption
B. adsorption
C. chemisorption
D. none of the mentioned
Answer» B. adsorption
Explanation: “chemisorption is the adsorption when interaction between the solid and the condensed molecules is relatively strong as contrasted with physical adsorption.
82.

The gas molecules are held on solid surface by                    in physical adsorption.

A. chemical forces
B. gravitational forces
C. electrostatic forces
D. vander waal’s forces
Answer» D. vander waal’s forces
Explanation: chemisorption is the adsorption when interaction between the solid and the condensed molecules is relatively strong as contrasted with physical adsorption.
83.

The extent of adsorption of a gas on a solid depend on

A. nature of gas
B. pressure of gas
C. temperature of the system
D. all of the mentioned
Answer» D. all of the mentioned
Explanation: the extent of adsorption of a gas on a solid depend on all three nature of gas, pressure of gas and temperature of the system.
84.

Which of the following gases is adsorbed by charcoal?

A. nh3
B. h2
C. n2
D. co2
Answer» A. nh3
Explanation: nh3 is easily liquefiable and highly water soluble gas.
85.

Langmuir isotherm Mathematical relation for                        that takes place at equilibrium.

A. absorption
B. adsorption
C. both adsorption and absorption
D. none of the mentioned
Answer» B. adsorption
Explanation: langmuir isotherm mathematical relation for adsorption that takes place at equilibrium.
86.

Adsorption process must be

A. endoethrgic
B. endothermic
C. exothermic
D. none
Answer» C. exothermic
Explanation: adsorption process is an exothermic process.
87.

The rate law for a reaction between the substances A and B is given by rate = K[A]n [B]m. On doubling the concentration of A and halving the concentration of B. What will be the ratio of the new rate of the earlier rate of the reaction?

A. (  1 )m+n
B. m2+n
C. n-m
D. 2n-m
Answer» D. 2n-m
88.

On which factor the rate constant of a reaction does not depend upon?

A. temperature
B. activation energy
C. catalyst
D. concentration of reactants and products
Answer» D. concentration of reactants and products
Explanation: the rate constant of reaction does not depend on concentration of reactant & product (only on nature of reactant & product).
89.

The rate of reaction, A + B Products, is given by the equation, r = k[A][B]. If B is taken in excess, what would be the order of reaction?

A. 2
B. 1
C. zero
D. unpredictable
Answer» B. 1
Explanation: a + b → products
90.

In a reaction, 2A2 + B2 → 2A2B, when the reactant A will disappear?

A. half the rate that b will decrease
B. the same rate that b will decrease
C. double the rate that a2b will form
D. twice the rate that b will decrease
Answer» D. twice the rate that b will decrease
91.

The rate of reaction that does not involve gases, is not dependent on                            

A. pressure
B. temperature
C. concentration
D. catalyst
Answer» A. pressure
Explanation: the rate of reaction that does not involve gases does not depend on pressure.
92.

Which is not true for a second order reduction?

A. it can have rate constant 1 x 10-2 l mol-1 s- 1
B. its half-life is inversely proportional to its initial concentration
C. time to complete 75% reaction is twice of half-life
D. t50 = 1/(ka⋅a0)
Answer» C. time to complete 75% reaction is twice of half-life
93.

The rate of decomposition of a substance increases concentration of substance at same temperature. Find out order of reaction.

A. 1
B. 2
C. 3
D. 0
Answer» B. 2
Explanation: rate = k [a]α r1 = k[a]n
94.

Molecularity of a reaction is equal to the total number of                            

A. products formed in the elementary step
B. reactants taking part in elementary step
C. reactants and products in the elementary step
D. reactants and products in the final step
Answer» B. reactants taking part in elementary step
Explanation: molecularity of a reaction is equal to the total number of reactants taking part in an elementary step. it is defined as the number of molecules or ions that participate in the rate determining step.
95.

Which of the following statement is incorrect about the molecularity of a reaction?

A. it is a theoretical concept
B. each step of a multi-step reaction has a unique molecularity
C. it is equal to the total number of reactants taking part in elementary step
D. it can be zero, fractional or integer
Answer» D. it can be zero, fractional or integer
Explanation: molecularity is always a whole number. it can be neither zero nor fractional. all the other options are correct.
96.

Which of the following factor does not effect the rate of reaction?

A. concentration of the reactant
B. temperature
C. pressure
D. effect of catalyst
Answer» C. pressure
Explanation: the reaction rate does not depend upon the pressure. it only depends upon the concentration of the reactant, temperature and effect of catalyst.
97.

The reaction rate is greatly influenced by

A. nature of bond in the reactant molecules
B. strength of bond in the reactant molecules
C. both nature and strength of the reactant molecules
D. it does not depend on either nature or strength of the reactant molecules
Answer» C. both nature and strength of the reactant molecules
Explanation: the reaction rate is greatly influenced by both nature and strength of the reactant molecules. reactants are the major factor that affects the rate of the reaction.
98.

The reactions register an increase in rates in the presence of radiations of specific wavelengths.

A. true
B. false
Answer» A. true
Explanation: the reactions register an increase in rates in the presence of radiations of specific wavelengths.
99.

Select the correct option from the following option.

A. catalyst is used to increase the rate of reaction by altering chemically during the course of reaction
B. catalyst is used to decrease the rate of reaction by altering chemically during the course of reaction
C. catalyst is used to increase the rate of reaction and remains unaltered chemically during the course of reaction
D. catalyst is used to decrease the rate of reaction and remains altered chemically during the course of reaction
Answer» C. catalyst is used to increase the rate of reaction and remains unaltered chemically during the course of reaction
Explanation: catalyst is used to increase the rate of reaction and remains unaltered chemically during the course of the reaction. with a catalyst, reactions occur faster and require less activation energy. because catalysts are not consumed in the catalyzed reaction, they can continue to catalyze the reaction of further quantities of reactant.
100.

Which of the following is not an adsorbent?

A. carbon
B. polymers and resins
C. clay
D. dry sponge
Answer» D. dry sponge
Explanation: a sponge will absorb or take in water from another area and put it inside of itself. a dry sponge can hold more water than a wet sponge is closer to saturation and as such cannot hold more water. sponges with more tiny holes can absorb more water than the sponges with less tiny holes and thus leads to the absorption process.
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