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Multiple choice question for engineering

Set 1

1. In mesomeric effect, the electrons are transferred from
a) A multiple bond to an atom
b) A multiple bond to a single covalent bond
c) An atom with lone pair to the adjacent single covalent bond
d) All of the mentioned

View Answer

Answer: d [Reason:] In mesomeric effect, the electrons are transferred from a multiple bond to an atom, a multiple bond to a single covalent bond and an atom with lone pair to the adjacent single covalent bond.

2. Which of the following is a resonance effect?
a) Inductive effect
b) Electromeric effect
c) Mesomeric effect
d) Inductomeric effect

View Answer

Answer: c [Reason:] Mesomeric effect is also known as resonance effect. The mesomeric effect is a permanent effect and operates in compounds containing at least one double bond.

3. The phenomenon in which 2 or more structures, involving identical position of atoms can be written for a particular molecule, is called
a) Conjugation
b) Resonance
c) Hyper conjugation
d) Vibration

View Answer

Answer: b [Reason:] The phenomenon in which 2 or more structures, involving identical position of atoms can be written for a particular molecule, is called resonance. The mesomeric effect is a permanent effect and operates in compounds containing at least one double bond.

4. Select the incorrect option from the following option.
a) Resonating structures have a real existence
b) The actual structure lies between various possible resonating structures
c) Resonating structures are useful as they allow us to describe molecules
d) None of the mentioned

View Answer

Answer: a [Reason:] Resonating structures have no real existence. All the other options are correct. The actual structure lies between various possible resonating structures, resonating structures are useful as they allow us to describe molecules.

5. The resonance energy is defined as difference in energy between
a) Two consecutive resonating structures
b) Resonance hybrid and most unstable resonating structure
c) Resonance hybrid and most stable resonating structure
d) First and last resonating structures

View Answer

Answer: c [Reason:] The resonance energy is defined as difference in energy between resonance hybrid and most stable resonating structure. The resonance energy of a compound is a measure of the extra stability of the conjugated system compared to the corresponding number of isolated double bonds.

6. Which of the following is application of mesomeric effect?
a) Dipole moment
b) Strength of acids and bases
c) Bond length
d) All of the mentioned

View Answer

Answer: d [Reason:] Dipole moment, strength of acids and bases and bond length are some of the applications of mesomeric effect.

7. State true or false. Dipole moment of CH3-CH2-Cl > CH2=CH-Cl.
a) True
b) False

View Answer

Answer: a [Reason:] Dipole moment of CH3-CH2-Cl > CH2=CH-Cl. This is due to resonance in vinyl chloride.

8. Select the correct statement from the following option.
a) Benzene ring have two different types of bond length for single and double bonds
b) All the bond length in benzene ring is equal due to hyperconjugation
c) All the bond length in benzene ring is equal due to resonance
d) All of the mentioned

View Answer

Answer: c [Reason:] All the bond length in benzene ring is equal due to resonance. All the bond lengths are equal in benzene ring i.e. double bond as well as single bond due to resonance.

9. Greater the number of resonating structures for a given intermediate,
a) Less will be its stability
b) More will be its stability
c) It will not effect its stability
d) None of the mentioned

View Answer

Answer: b [Reason:] Greater the number of resonating structures for a given intermediate, more will be its stability. More resonating structure increases the stability.

10. Phenyl group show
a) (+M) effect
b) (+E) effect
c) (+I) effect
d) (-M) effect

View Answer

Answer: d [Reason:] Phenyl group show (-M) effect. The phenyl group or phenyl ring is a cyclic group of atoms with the formula C6H5.

Set 2

1. Vibrational spectroscopy involves the transitions falling in the spectral range of
a) 100-1000 cm-1
b) 300-3000 cm-1
c) 400-4000 cm-1
d) 500-5000 cm-1

View Answer

Answer: c [Reason:] Vibrational spectroscopy involves the transitions falling in the spectral range of 400-4000 cm-1 (infrared region).

2. Which of the region of IR spectra appears between (1400-600) cm-1?
a) Functional group region
b) Fingerprint region
c) Low-frequency region
d) None of the mentioned

View Answer

Answer: b [Reason:] Fingerprint region of IR spectra appears between (1400-600) cm-1.

3. Select the correct statement from the following option.
a) Infrared spectra can identify the unknown materials
b) It can determine the amount of components in a mixture
c) It can also determine the quality of a sample
d) All of the mentioned

View Answer

Answer: d [Reason:] Infrared spectra can identify the unknown materials. It can determine the amount of components in a mixture and can also determine the quality of a sample.

4. Which of the following molecule have infrared active vibrations?
a) NO
b) CH4
c) H2
d) All of the mentioned

View Answer

Answer: a [Reason:] NO molecule have infrared active vibrations. Infrared spectra can identify the unknown materials. It can determine the amount of components in a mixture and can also determine the quality of a sample.

5. Which of the following cannot show a vibrational absorption spectrum?
a) OCS
b) H2O
c) CO 2
d) C H2 = C H2

View Answer

Answer: d [Reason:] C H2 = C H2 cannot show vibrational absorption spectrum. OCS, H2O and CO 2 can show a vibrational absorption spectrum.

6. Which of the following is not a type of bending molecular vibration?
a) Twisting
b) Stretching
c) Wagging
d) Rocking

View Answer

Answer: b [Reason:] Stretching is not a type of bending molecular vibration. Twisting, wagging and rocking are types of bending molecular vibration.

7. What is the absorption frequency(cm-1) of –C=N functional group?
a) 3610-3640
b) 1690-1760
c) 1180-1360
d) 2850-2960

View Answer

Answer: c [Reason:] The absorption frequency for –C=N group is 1180-1360 cm-1. Absorption spectroscopy refers to spectroscopic techniques that measure the absorption of radiation, as a function of frequency or wavelength, due to its interaction with a sample.

8. Presence of functional group in a compound can be established by using
a) Chromatography
b) IR spectroscopy
c) Mass spectroscopy
d) X-ray diffraction

View Answer

Answer: b [Reason:] Presence of functional group in a compound can be established by using IR spectroscopy. It is the spectroscopy that deals with the infrared region of the electromagnetic spectrum, that is light with a longer wavelength and lower frequency than visible light.

9. Select the incorrect option from the following option.
a) IR spectroscopy helps in determination of purity
b) IR spectroscopy helps in determination of force constant from vibrational spectrum
c) IR spectroscopy helps in identifying an unknown compound
d) None of the mentoned

View Answer

Answer: d [Reason:] All the options are correct. IR spectroscopy helps in determination of purity, force constant from vibrational spectrum and identifying an unknown compound.

10. State true or false. IR spectroscopy helps in detecting presence of hydrogen bonding.
a) True
b) False

View Answer

Answer: a [Reason:] IR spectroscopy helps in detecting presence of hydrogen bonding. It is the spectroscopy that deals with the infrared region of the electromagnetic spectrum, that is light with a longer wavelength and lower frequency than visible light.

Set 3

1. The B.E.T. theory was proposed in the year
a) 1940
b) 1935
c) 1938
d) 1945

View Answer

Answer: c [Reason:] Brunauer, Emmett and Teller proposed a theory in 1938 which is known as B.E.T. theory.

2. The B.E.T. theory was based on the
a) Single layer adsorption
b) Multilayer adsorption
c) Double layer adsorption
d) None of the mentioned

View Answer

Answer: b [Reason:] The B.E.T. theory was based on the multilayer adsorption. It aims to explain the physical adsorption of gas molecules on a solid surface and serves as the basis for an important analysis technique for the measurement of the specific surface area of a material.

3. Which of the following is an assumption for B.E.T theory?
a) The solid surface possess uniform, localised sites
b) The adsorption at one site does not affect adsorption at neighbouring site
c) Physical adsorption of adsorbate occurs resulting in formation of multilayers
d) All of the mentioned

View Answer

Answer: d [Reason:] The assumptions for B.E.T theory are – the solid surface possess uniform, localised sites, the adsorption at one site does not affect adsorption at neighbouring site and physical adsorption of adsorbate occurs resulting in formation of multilayers, etc.

4. The energy of adsorption in first layer is
a) Increasing
b) Decreasing
c) Constant
d) None of the mentioned

View Answer

Answer: c [Reason:] The energy of adsorption in first layer is constant. It aims to explain the physical adsorption of gas molecules on a solid surface and serves as the basis for an important analysis technique for the measurement of the specific surface area of a material.

5. The surface area available for the nth layer is equal to the coverage of
a) (n-1)th layer
b) (n+1)th layer
c) nth layer
d) None of the mentioned

View Answer

Answer: a [Reason:] The surface area available for the nth layer is equal to the coverage of (n-1) th layer. By application of the BET theory, it is possible to determine the inner surface of hardened cement paste.

6. In the B.E.T. equation, what does p0 denotes?
a) Pressure of the gas molecules
b) Unsaturated vapor pressure of the gas molecules
c) Saturated vapor pressure of the gas molecules
d) All of the mentioned

View Answer

Answer: c [Reason:] In the B.E.T. equation, p0 denotes the saturated vapour pressure of the gas molecules at the same temperature.

7. According to B.E.T. equation, the plot of P/V(P0-P) versus P/P0 will yield a
a) Straight line
b) Parabola
c) Hyperbola
d) Eclipse

View Answer

Answer: a [Reason:] According to B.E.T. equation, the plot of P/V(P0-P) versus P/P0 will yield a straight line. By application of the BET theory, it is possible to determine the inner surface of hardened cement paste.

8. The B.E.T. theory is used in calculating the
a) Surface area of adsorbate
b) Surface area of adsorbent only
c) Surface area of adsorbents and catalyst
d) None of the mentioned

View Answer

Answer: c [Reason:] The B.E.T. theory is used in calculating the surface area of adsorbents and catalyst. By application of the BET theory, it is possible to determine the inner surface of hardened cement paste.

9. The surface area occupied by single gas molecule is inversely proportional to the
a) Molar mass of the gas adsorbed
b) Density of the liquefied gas
c) Volume of the gas
d) All of the mentioned

View Answer

Answer: b [Reason:] The surface area occupied by single gas molecule is inversely proportional to the density of the liquefied gas. Porous inorganic materials such as mesoporous silica and layered clay minerals have high surface areas of several hundred m2g−1 calculated by the BET method.

10. The total surface area covered by all the molecules of the adsorbed gas is given by
a) S = nβ/NA
b) S = βNA/n
c) S = nβNA
d) S = NA/nβ

View Answer

Answer: c [Reason:] The total surface area covered by all the molecules of the adsorbed gas is given by S = nβNA. The surface area occupied by single gas molecule is inversely proportional to the density of the liquefied gas.

Set 4

1. What is calgon?
a) Potassium hexa meta sulphate
b) Magnesium hexa meta phosphate
c) Sodium hexa meta phosphate
d) Calcium hexa meta sulphate

View Answer

Answer: c [Reason:] Calgon is sodium hexa meta phosphate. Calgon prevents limescale build-up in washing machines all over the world to protect the heating element, pipes and drum of the machines.

2. Calgon is added to boiler water to prevent
a) Foaming
b) Sludge and scale formation
c) Priming
d) Corrosion

View Answer

Answer: b [Reason:] Calgon is added to boiler water to prevent sludge and scale formation. Calgon prevents limescale build-up in washing machines all over the world to protect the heating element, pipes and drum of the machines.

3. Calgon converts the scale forming impurity like CaSO4 into
a) Soluble complex compound
b) Insoluble complex compound
c) Soluble acids
d) Insoluble acids

View Answer

Answer: a [Reason:] Calgon converts the scale forming impurity like CaSO4 into soluble complex compound which are harmless to boiler.

4. The quantity of calgon to be added to prevent scale and sludge formation is
a) 10-20 ppm
b) 30-50 ppm
c) 0.005-0.1 ppm
d) 0.5-5 ppm

View Answer

Answer: d [Reason:] The quantity of calgon to be added to prevent scale and sludge formation is 0.5-5 ppm. It is used in small quantity.

5. At high temperature and pressure, calgon is converted into sodium ortho-phosphate which reacts with ____________ salts .
a) Magnesium
b) Calcium
c) Sodium
d) Potassium

View Answer

Answer: b [Reason:] At high temperature and pressure, calgon is converted into sodium orthophosphate which reacts with calcium salts to form calcium ortho-phosphate.

6. State true or false. Calcium ortho-phosphate appears as loose sludge and thus can be removed by blow-down operation.
a) True
b) False

View Answer

Answer: a [Reason:] Calcium orthophosphate appears as loose sludge and thus can be removed by blow-down operation. It is formed by the reaction of sodium ortho-phosphate with calcium salts.

7. Calgon conditioning is not applicable for the prevention of
a) Iron oxide only
b) Copper depositions only
c) Sulphurdioxide only
d) Iron oxide and copper depositions

View Answer

Answer: d [Reason:] Calgon conditioning is not applicable for the prevention of iron oxide and copper depositions. Calgon prevents limescale build-up in washing machines all over the world to protect the heating element, pipes and drum of the machines.

8. Iron oxide and copper depositions can be prevented by adding ___________ to the boiler water.
a) Calgon
b) Carbonate
c) EDTA
d) EBT

View Answer

Answer: c [Reason:] Iron oxide and copper depositions can be prevented by adding EDTA to the boiler water. Ethylenediaminetetraacetic acid (EDTA), is an amino poly-carboxylic acid and a colorless and a water-soluble solid.

9. Carbonate conditioning is not done in high pressure boilers because it may lead to caustic embrittlement. State true or false.
a) True
b) False

View Answer

Answer: a [Reason:] Carbonate conditioning is not done in high pressure boilers because it may lead to caustic embrittlement. Caustic embrittlement is the phenomenon in which the material of a boiler becomes brittle due to the accumulation of caustic substances.

10. Which of the following is not used in colloidal conditioning?
a) Kerosene
b) Tannin
c) Agar-agar
d) Vinegar

View Answer

Answer: d [Reason:] Kerosene, tannin and agar-agar is used in colloidal conditioning. Vinegar is not used for this purpose.

Set 5

1. Which of the following factor influences the rate and extent of corrosion?
a) Nature of metal only
b) Nature of environment only
c) Both nature of metal and environment
d) Nature of reaction

View Answer

Answer: c [Reason:] Both nature of metal and environment influences the rate and extent of corrosion as corrosion is a natural process, which converts a refined metal to a more stable form, such as its oxide, hydroxide, or sulfide. .

2. Which of the following is not associated with the nature of metal?
a) Nature of oxide film
b) Nature of electrolyte
c) Purity
d) Physical state

View Answer

Answer: b. [Reason:] Nature of metal includes its purity, physical state, nature of oxide film, position in galvanic series, etc and hence it is not associated with the nature of electrolyte.

3. Which of the following is not associated with the nature of environment?
a) Humidity
b) Temperature
c) Effect of pH
d) Volatility of corrosion products

View Answer

Answer: d [Reason:] Nature of environment includes temperature, humidity, effect of pH, nature of electrolyte, etc and hence volatility of corrosion product is not associated with it.

4. State true or false. Lesser is the purity of percentage of metal, faster is the rate of corrosion.
a) True
b) False

View Answer

Answer: a [Reason:] Lesser is the purity of percentage of metal, faster is the rate of corrosion. Pure metals does not corrose easily whereas impure metals corrode easily.

5. Rate of corrosion of anodic region is inversely proportional to the
a) Cathodic area
b) Anodic area
c) Product of anodic area and cathodic area
d) Sum of anodic area and cathodic area

View Answer

Answer: b [Reason:] Rate of corrosion of anodic region is inversely proportional to the anodic area. Greater will be the anodic area, faster will be the corrosion at anode.

6. Corrosion of zinc can be minimized by increasing the pH to
a) 9
b) 10
c) 11
d) 12

View Answer

Answer: c [Reason:] Corrosion of zinc can be minimized by increasing the pH to 11. pH 11 means it will be basic in nature and hence will be less prone to corrosion.

7. Which of the following medium is most corrosive?
a) Acidic
b) Alkaline
c) Neutral
d) Both acidic and basic

View Answer

Answer: a [Reason:] Acidic medium is more corrosive than alkaline and neutral media. In acidic medium, metals are more reactive and more prone to corrosion.

8. Which of the following is an example of inactive atmospheric suspended particle?
a) NaCl
b) (NH4)2 SO4
c) AlCl3
d) Charcoal

View Answer

Answer: d [Reason:] Charcoal is an example of inactive atmospheric suspended particle. Charcoal is obtained by removing water and other volatile constituents from animal and vegetation substances.

9. Excessive corrosion of metal takes place if corrosion product is
a) Volatile
b) Non-volatile
c) Both volatile as well as non-volatile
d) Initially volatile and then non-volatile

View Answer

Answer: a [Reason:] Excessive corrosion of metal takes place if corrosion product is volatile. When the corrosion product is volatile it easily escapes with gases and hence allowing more metal to corrode.

10. The specific volume ratios of W, Cr and Ni are 3.6, 2.0 and 1.6 respectively. Which of them will have the least rate of corrosion?
a) Ni
b) Cr
c) W
d) All will have same rate of corrosion

View Answer

Answer: c [Reason:] W will have the least rate of corrosion, even at higher temperatures because specific volume ratio is inversely proportional to the rate of corrosion.