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# Multiple choice question for engineering

## Set 1

1. Conductivity is defined as the ability to carry
a) Voltage
b) Resistance
c) Current
d) All of the mentioned

Answer: c [Reason:] Conductivity is defined as the ability to carry current. It is measured by the flow of electrons and charges through a conductor.

2. The reciprocal of conductivity is
a) Viscosity
b) Resistivity
c) Turbidity
d) None of the mentioned

Answer: b [Reason:] The reciprocal of conductivity is resistivity. It is the measure of resistance provided in the path of electrons.

3. Which of the following is specific conductivity reagent?
a) KCl
b) HCl
c) NaCl
d) MgCl2

Answer: a [Reason:] KCl is a specific conductivity reagent. Specific conductance is a measure of the electric current in the water sampled carried by the ionized substances.

4. The internationally recommended unit for conductance is
a) Poise
b) Dyne
c) Ohm
d) Siemens

Answer: d [Reason:] The internationally recommended unit for conductance is Siemens (S). 1 siemen = 1 ohm-1

5. The cell constant is defined as the ratio of
a) Area of either electrodes to the length between the electrodes
b) Length between the electrodes to the area of either electrodes
c) Length between the electrodes to the volume of either electrode
d) Resistivity to conductivity

Answer: b [Reason:] The cell constant is defined as the ratio of length between the electrodes to the area of either electrodes. It only depends upon the physical dimension of the cell.

6. Choose the correct order of molar ionic conductivities of the following ions.
a) Li+ < Na+ < K+ < Rb+
b) Li+ < K+ < Rb+ < Na+
c) Li+ < Na+ < Rb+ < K+
d) Li+ < Rb+ < Na+ < K+

Answer: a [Reason:] the correct order of molar ionic conductivity is- Li+ < Na+ < K+ < Rb+.

7. On which factor does the conductance of electrolytic solution depends?
a) Temperature and pressure
b) Number of charge carriers
c) Dielectric constant of the solvent
d) All of the mentioned

Answer: d [Reason:] The factors on which conductance of electrolytic solution depends are- Temperature, pressure, number of charge carriers and dielectric constant of the solvent.

8. On dilution, the specific conductance
a) Increases
b) Remains same
c) Decreases
d) None of the mentioned

Answer: c [Reason:] On dilution, the specific conductance decreases because dilution decreases the concentration of the solution.

9. The equivalent conductance of 0.1 H2SO4offering a resistance of 50ohms when placed in a conductivity cell whose electrodes are 1cm apart with a cross-sectional area of 2cm2 at 250C is
a) 100 S cm2 eq-1
b) 1000 S cm2 eq-1
c) 10 S cm2 eq-1
d) 1 S cm2 eq-1

Answer: a [Reason:] The equivalent molar conductance is 100 S cm2 eq-1. Conductivity = Conductance * cell constant Cell constant = Length / Area

10. Dilution means increase in the amount of
a) Solute
b) Solvent
c) Electrolyte
d) All of the mentioned

Answer: b [Reason:] Dilution means increase in the amount of solvent and hence it decreases the concentration of solute particles.

## Set 2

1. Conformations are different arrangements of atoms that can be converted into one another by rotation about
a) Covalent bond
b) Double bond
c) Single bond
d) Triple bond

Answer: c [Reason:] Conformational isomerism is a form of stereoisomerism in which the isomers can be interconverted exclusively by rotations about formally single bonds. Such isomers are generally referred to as conformational isomers or conformers and, specifically, as rotamers.

2. The energy required to rotate n-butane molecule about the carbon-carbon bond is called
a) Rotational energy
b) Torsional energy
c) Enantiomeric energy
d) Potential energy

Answer: b [Reason:] The energy required to rotate n-butane molecule about the carbon-carbon bond is called torsional energy. Torsion energy can be used to solve problems of general relativity especially the singularity problem.

3. The rotation about the (C2 – C3) carbon-carbon bond of n-butane requires the energy of about
a) 100 kJ/mol
b) 50 kJ/mol
c) 10 kJ/mol
d) 3 kJ/mol

Answer: d [Reason:] The rotation about the (C2 – C3) carbon-carbon bond of n-butane requires the very less energy of about 3kJ/mol. It requires very less amount of energy.

4. The infinity of intermediate conformations are called
a) Skew conformations
b) Staggered conformations
c) Eclipsed conformations
d) Gauche

Answer: a [Reason:] The infinity of intermediate conformations are called skew conformations. Three conformations of cyclohexane, designated as chair, boat, and skew (or twist), are essentially free of angle strain.

5. The potential energy of n-butane is minimum for
a) Skew conformations
b) Staggered conformations
c) Eclipsed conformations
d) Gauche

Answer: b [Reason:] The potential energy of n-butane is minimum for staggered conformations. It is because of no steric hinderance.

6. The potential energy of n-butane is maximum for
a) Skew conformations
b) Staggered conformations
c) Eclipsed conformations
d) Gauche

Answer: c [Reason:] The potential energy of n-butane is maximum for eclipsed conformations. It is because of overlapping of functional groups.

7. The relative instability of any of the intermediate skew conformations is due to
a) Lateral strain
b) Shear strain
c) Longitudinal strain
d) Torsional strain

Answer: d [Reason:] The relative instability of any of the intermediate skew conformations is due to torsional strain. Torsion energy can be used to solve problems of general relativity especially the singularity problem.

8. In gauche conformations, the methyl groups are
a) 600 apart
b) 900 apart
c) 1800 apart
d) 3600 apart

Answer: a [Reason:] In gauche conformations, the methyl groups are 600 apart. In general a gauche rotamer is less stable than an anti-rotamer.

9. State true or false. Both anti and gauche conformations are free of torsional strain.
a) True
b) False

Answer: a [Reason:] Both anti and gauche conformations are free of torsional strain. In general a gauche rotamer is less stable than an anti-rotamer.

10. Gauche conformation is less stable due to
a) Hydrogen bonding
b) Covalent bonding
c) Vander Waal’s repulsion
d) Torsional strain

Answer: c [Reason:] Gauche conformation is less stable due to Vander Waal’s repulsion. Vander Waal’s are weak forces of attraction which results in lesser stability of gauche conformer.

11. Which of the following is least stable?
a) Anti conformation
b) Gauche conformation
c) Staggered conformation
d) Eclipsed conformation

Answer: d [Reason:] Eclipsed conformation is least stable due to its high torsional energy. The potential energy of n-butane is maximum for eclipsed conformations.

12. State true or false. Potential energy remains same during the rotation about the carbon-carbon of n-butane.
a) True
b) False

Answer: b [Reason:] Potential energy changes during the rotation about the carbon-carbon of n-butane. The potential energy of n-butane is maximum for eclipsed conformations and minimum for staggered conformations.

## Set 3

1. Which of the following is not a common method used for purification?
a) Sublimation
b) Crystallisation
c) Electrolysis
d) Chromatography

Answer: c [Reason:] Sublimation, crystallisation, distillation, differential extraction and chromatography are some of the common methods used for purification. Electrolysis process is not used for this purpose.

2. Crystallisation is based on the
a) Difference in melting point
b) Difference in boiling point
c) Difference in pressure
d) Difference in solubility

Answer: d [Reason:] Crystallisation is based on the difference in the solubility of the compound and the impurities in a suitable solvent.

3. Which of the following is the example of crystallisation process?
a) Purification of alum
b) Purification of sea water
c) Separation of gases from air
d) None of the mentioned

Answer: a [Reason:] An impure sample of alum or copper sulphate is purified by crystallisation process. Purification of sea water is example of distillation process.

4. At room temperature, the impure compound in crystallisation is
a) Soluble
b) Sparingly soluble
c) Insoluble
d) None of the mentioned

Answer: b [Reason:] The impure compound is sparingly soluble in a solvent at room temperature but appreciably soluble at higher temperatures.

5. Which of the following is known as mother liquor?
a) Solvent
b) Solute
c) Solution
d) Filtrate

Answer: d [Reason:] The filtrate is also known as mother liquor. A mother liquor is the part of a solution that is left over after crystallization. It is encountered in chemical processes including sugar refining.

6. The solution of impure compound and solvent is concentrated to get
a) Unsaturated solution
b) Undersaturaed solution
c) Saturated solution
d) Oversaturated solution

Answer: c [Reason:] The solution of impure compound and solvent is concentrated to get a saturated solution. The solution is filtered to remove insoluble impurities.

7. Insoluble impurities from solution during crystallization are removed by
a) Drying
b) Filtration
c) Heating
d) Cooling

Answer: b [Reason:] Insoluble impurities from solution during crystallization are removed by filtration. The solution is filtered to remove insoluble impurities.

8. The solution which is obtained after filtration is
a) Suspended solution
b) Clear solution
c) Colloidal solution
d) None of the mentioned

Answer: b [Reason:] The solution which is obtained after filtration is clear solution. The solution is filtered to remove insoluble impurities.

9. Crystal phases can be inter-converted by varying
a) Temperature
b) Pressure
c) Size
d) Viscosity

Answer: a [Reason:] Crystal phases can be inter-converted by varying factors such as temperature.

10. The nature of crystallisation process is governed by
a) Thermodynamics
b) Kinetic factors
c) Thermodynamics and Kinetic factors
d) None of the mentioned

Answer: c [Reason:] The nature of crystallisation process is governed by both thermodynamics and kinetic factors.

## Set 4

1. The greek meaning of Dendron is
a) Stem
b) Branch
c) Tree
d) Root

Answer: c [Reason:] The greek meaning of Dendron is tree. Synonymous terms for dendrimer include arborols and cascade molecules.

2. Which of the following is not the other name for dendrimers?
a) Dendritic
b) Starburst
d) Deluge polymers

Answer: d [Reason:] Dendrimers are also known as dendritic, starburst and cascade polymers. Synonymous terms for dendrimer include arborols and cascade molecules. Deluge is not used with dendrimers.

3. Which of the following is not a component of dendrimer?
a) Central core
b) Stem
c) Interior dendritic structure
d) Exterior surface

Answer: b [Reason:] The dendrimer has three components,i.e. central core, interior dendritic structure and the exterior surface. No stem is present in the dendrimer.

4. State true or false. Dendrimers resemble star polymers except that each leg of the star exhibits repetitive branching in the manner of a tree.
a) True
b) False

Answer: a [Reason:] Dendrimers resemble star polymers except that each leg of the star exhibits repetitive branching in the manner of a tree. Dendritic molecules are characterized by structural perfection.

5. As dendrimers have high surface functionality, so they tend to be _________ soluble than linear polymers.
a) More
b) Less
c) Equally
d) Very less

Answer: a [Reason:] As dendrimers have high surface functionality, so they tend to be more soluble than linear polymers. The properties of dendrimers are dominated by the functional groups on the molecular surface, however, there are examples of dendrimers with internal functionality.

6. Due to lack of chain entanglement, dendrimers usually have low
a) Solubility
b) Boiling point
c) Viscosity
d) Conductivity

Answer: c [Reason:] Due to lack of chain entanglement, dendrimers usually have low viscosity. The properties of dendrimers are dominated by the functional groups on the molecular surface, however, there are examples of dendrimers with internal functionality.

7. The molecular dimensions of dendrimers lie in the range of
a) 1-100 nm
b) 100-500 nm
c) 600-800 nm
d) 800-1000 nm

Answer: a [Reason:] The molecular dimensions of dendrimers lie in the range of 1-100 nm. So, dendrimers can be used as a solubilizing agent.

8. Which of the following is not a potential application of dendrimer?
a) Viscosity modifier
b) Molecular sensors
c) Drug delivery system
d) Temperature modifier

Answer: d [Reason:] Temperature modifier is not a potential application of dendrimer. All the other options including viscosity modifier, molecular sensors and drug delivery system are potential applications of dendrimer.

9. State true or false. Dendrimers have the potential for mimicking the behaviour of microscopic and macroscopic molecules.
a) True
b) False

Answer: b [Reason:] Dendrimers have the potential for mimicking the behaviour of only nanoscopic molecules.

10. There is a limit to the size of dendrimer segments because of
a) Low viscosity
b) High solubility
c) Steric congestion

Answer: c [Reason:] There is a limit to the size of dendrimer segments because of steric congestion. Dendrimers and dendrons are mono-disperse and usually highly symmetric, spherical compounds.

## Set 5

1. The example of brackish water is
a) Ground water
b) Rain water
c) Sea water
d) Underground water

Answer: c [Reason:] The example of brackish water is sea water. Ground water, underground water and rain water are not brackish water. Sea water is also saline in nature and not fit for domestic purpose.

2. Which of the following technique is not used for the desalination of brackish water?
a) Electrolysis
b) Electrodialysis
c) Reverse osmosis
d) Distillation

Answer: a [Reason:] Electrolysis technique is not used for the desalination of brackish water. Electrodialysis, reverse osmosis and distillation are the few techniques used for desalination of brackish water.

3. State true or false. Salt cannot be separated from brackish water by freezing.
a) True
b) False

Answer: b [Reason:] Salt can be separated from brackish water by freezing.

4. 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 [Reason:] 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.

5. 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 [Reason:] The cation selective membrane is embedded with functional groups of negative charge as it attracts only positive charges towards them.

6. In electrodialysis cell, the pressure is about
a) 2 kg/m2
b) 3 kg/m2
c) 5-6 kg/m2
d) 10 kg/m2

Answer: c [Reason:] Electrodialysis is an electrically driven separation conducted at very low pressure-driven of about 5-6 kg/m2.

7. State true or false. Electrodialysis is an electrically driven separation conducted at very low pressure-driven, size-exclusion filtering process.
a) True
b) False

Answer: a [Reason:] Electrodialysis is an electrically driven separation conducted at 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.

8. 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 [Reason:] The ion-exchange membrane are electrically conductive and impermeable to water flow, even under pressure. Electrons can easily flow through these membranes.

9. 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