Additional Questions ChT Flashcards by Mary Regine Calamba

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

c. Electrolysis

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Crystallization is based on the

Difference in solubility

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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

a) Purification of alum

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At room temperature, the impure compound in crystallization is

Sparingly soluble

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Which of the following is known as mother liquor

Filtrate

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The solution of impure compound and solvent is concentrated to get

Saturated solution

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Insoluble impurities from solution during crystallization are removed by

Filtration

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The solution which is obtained after filtration is

Clear solution

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Crystal phases can be inter-converted by varying

Temperature

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The nature of the crystallization process is governed by

Thermodynamics and Kinetic factors

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The process of heating a liquid mixture to form vapours and then cooling the vapours to get pure component is called

Distillation

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Porcelain pieces are put into the distillation flask to avoid

Bumping of the solution

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The boiling point of chloroform is

334 K

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The boiling point of aniline is

457 K

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How aniline and chloroform can be separated?

Distillation

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Which of the following is not separated through distillation process?
a) Acetone and water
b) Aniline and chloroform
c) Impurities in Sea water
d) Milk and water

d. Milk and water

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Which of the following will vaporize faster?
a) Aniline
b) Chloroform
c) Water
d) Kerosene

b) Chloroform

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The distilled water is collected in

Receiver

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The process of distillation is used for the liquids having

Sufficient difference in their boiling point

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(Distillation) The residue in the round bottom flask is

Non volatile

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Fractional distillation is a process of separation of

2 miscible liquids

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The difference in boiling point of 2 liquids in fractional distillation is

less than 25 K

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(Fractional distillation) A simple fractional tube is packed with

Glass beads

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Fractional distillation is different from distillation because of the presence of

Fractionating column

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The beads are provided in fractional column for

Vapours to condense

Select the INCORRECT statement from the following options. a) Fractionating columns are available in various design and size b) Fractionating columns are available according to one fixed standard c) A simple fractionating column is a tube packed with glass beads d) Fractional distillation is the process of separation of different gases from air

b) Fractionating columns are available according to one fixed standard

Which of the following gases cannot be separated from air using fractional distillation? a) Argon b) Oxygen c) Helium d) Nitrogen

c) Helium

(Fractional distillation) Initially, the temperature at the top of the column is _______________ than at its bottom.

Lesser

Which of the following is more suitable for fractional distillation process? a) Oil bath b) Water bath c) Glycerine bath d) None of the mentioned

Oil bath

Number of steps required for the separation of two liquids in fractional distillation is

In steam distillation, the liquid boils when the sum of vapour pressure due to organic liquid and due to water becomes

Equals to atmospheric pressure

The organic liquid in steam distillation vaporizes at

Lower temperature than its boiling point

Steam distillation process is used to separate substances which are

Steam volatile and immiscible with water

What type of mixture is collected in round bottom flask after passing through a steam generator?

Mixture of volatile organic compound and steam

Which of the following property is NOT possessed by the organic solvent required to separate organic compound with water? a) It is immiscible with water b) It is less volatile than water c) It is easily vaporisable d) Organic compound is more soluble in it

It is less volatile than water

Which of the following is the upper layer in differential extraction? a) Solvent layer b) Solute layer c) Aqueous layer d) None of the mentioned

Solvent layer

When does the organic compound be present in the upper solvent layer in differential extraction?

After the extraction

The organic compound in differential extraction is recovered from the organic solvent by

Distillation

The pure solvent after the differential extraction cannot be used again for the extraction.

FALSE

Aniline is separated from aniline-water mixture using

Steam distillation

Chromatography is the process for identification, purification and separation of components of a mixture on the basis of

Difference in their affinity for mobile and stationary phase

Chromatography involves two mutually

Immiscible phases

(Chromatography) There is no need of support if packed into a column when the stationary phase is

Solid

Which of the following is not a stationary phase? a) Liquid-liquid chromatography b) Gas-liquid chromatography c) Gas-solid chromatography d) Solid-solid chromatography

d) Solid-solid chromatography

Liquid chromatography is a technique for separating

Ions that are dissolved in a solvent

In exclusion chromatography, solute molecules are separated based on

Molecular geometry and size

The gas-solid chromatography is ______________ chromatography as per basic principle involved.

Adsorption

(Chromatography) A proper solvent that is passed through the column for elution so that separated components can be collected is called

Buffer solution

(Chromatography) The relative solubility of solute in both the phases determines the

Rate of movement of solute

(Chromatography) If the mobile phase is gas, movement of solute is determined by its

Volatility

Column chromatography is based on the principle of

Differential adsorption

(Column chromatography) Arrange the following compounds in order of their increasing adsorption tendencies

Cellulose >> starch >> calcium carbonate >> alumina

What is the factor responsible for the separation in column chromatography?

Polarity differences between the solute

(Column chromatography) Select the correct statement from the following options. a) The lesser the polarity of solute, more strongly it will be adsorbed on a polar surface b) The greater the polarity of solute, more weakly it will be adsorbed on a polar surface c) The greater the polarity of solute, more strongly it will be adsorbed on a polar surface d) All of the mentioned option

c) The greater the polarity of solute, more strongly it will be adsorbed on a polar surface

(Column Chromatography) The correct order of increasing strength of adsorption is

Alkanes >> Esters >> Ketones >> Aldehydes >> Phenols

The components of the mixture in column chromatography are eluted in order of

Increasing polarity and increasing distribution ratio

(Column chromatography) The elution power of a solvent is determined by ____________ a) Its overall polarity b) The polarity of the stationary phase c) The nature of the sample components d) All of the mentioned

d) All of the mentioned

Which of the following is separated through column chromatography? a) Chlorophyll and carotenoids b) Inorganic cations or complexes c) Sugar derivatives d) Amino acids formed by hydrolysis of a protein molecule

a) Chlorophyll and carotenoids

(Column chromatography) 9. The mixture of petroleum ether and benzene is used in the elution ratio of

01:09

(Column chromatography) Chloroform fraction is eluted from the column by passing chloroform through the column which acts as

Elution

The principle on which thin layer chromatography is based is that the

Different compounds are adsorbed on an adsorbent to different degrees

(Thin layer chromatography) The size of a thin layer of adsorbent is about

0.2 mm

The chromaplate or thin layer chromatography plate is made up of

Glass

(Thin layer chromatography) The eluant filled in the closed jar is

Mixture of liquids

(Thin layer chromatography) Select the incorrect statement from the following options. a) The spots of colorless compounds are invisible to the eyes b) These spots can be detected by putting the plate under ultraviolet light c) These spots can be detected by placing the plate in a covered jar containing iodine crystals d) None of the mentioned

d) None of the mentioned

(Thin layer chromatography) The relative adsorption of each component of the mixture is expressed in terms of its

Retardation factor

(Thin layer chromatography) Select the correct statement from the following. a) Paper chromatography is a type of partition chromatography b) A special quality paper is used in paper chromatography c) Chromatography paper contains water trapped in it, which acts as stationary phase d) All of the mentioned

All of the above

(Thin layer chromatography) Amino acids detected by spraying the plate with ninhydrin solution is an example of

Paper chromatography

Paper chromatography is based on continuous differential partitioning of components of a mixture between stationary and mobile phases.

TRUE

(Thin layer chromatography) Retardation factor is the ratio of

Distance moved by substance from base line to distance moved by the solvent from base line

What are the uses of partition chromatography? a) Separation of amino acids b) Analysis of closely related aliphatic alcohols c) Separation of sugar derivatives d) All of the mentioned

All of the mentioned

Which type of chromatography is used for the structural analysis?

Paper chromatography

Which of the following is not done using column chromatography? a) The identification of unknown compounds b) The determination of homogeneity of chemical substances c) Separation of inorganic cations or complexes d) Separation of geometric isomers

Separation of inorganic cations or complexes

Affinity chromatography is used for the analysis and isolation of ____________ a) Insoluble starch substances b) Enzyme tyrosinase c) Antibodies bound with a covalently-attached antigen on cellulose column d) All of the mentioned

d) All of the mentioned

Purification of enzymes and proteins is done using

Affinity chromatography

Which of the following is not an application of high performance liquid chromatography? a) Analysis of proteins, drugs and explosives b) Separation of pharmaceutical drugs c) Elimination of undesirable substances from blood d) Separation of lipids, fatty acids and steroids

c) Elimination of undesirable substances from blood

The checking of purity of samples is the application of thin layer chromatography.

TRUE

The analysis and separation of industrial products like soap and synthetic detergents is done using

Gas chromatography

Which of the following is the application of ion exchange chromatography? a) The softening of hard water b) The demineralisation of water c) The separation and determination of anions d) All of the mentioned

d) All of the mentioned

The quantitative analysis is done using

Gas chromatography

The purity of the compound is confirmed by ____________ a) Its melting point and boiling point b) Chromatographic technique c) Spectroscopy d) All of the mentioned

All of the mentioned

Select the correct statement from the following options. a) The transformation of solid to liquid is called melting and the reverse process is called freezing b) The transformation of solid to liquid is called freezing and the reverse process is called melting c) The transformation of liquid to solid is called melting and the reverse process is called freezing d) None of the mentioned

The transformation of solid to liquid is called melting and the reverse process is called freezing

The temperature at which solid and liquid coexist in equilibrium is called

Freezing point of liquid

Select the incorrect statement from the following option. a) Every pure solid crystalline substance has a characteristic and unique melting point b) Impure sample of substance has different melting point c) Two different pure substances have same melting points d) Melting point serves as the criteria of purity of a solid substance

Two different pure substances have same melting points

When the solid and liquid phase are in equilibrium, the temperature

Remains constant

The melting point of ice is

0 deg C

Molar heat of fusion is defined as

Energy required to melt one mole of solid

The temperature remains constant during phase change because the increased kinetic energy is used to overcome the cohesive forces in the liquid.

TRUE

What is the molar heat of fusion (kJ/mol) of water?

6.01

What is the melting point of mercury?

b) -39 deg C

On increasing the temperature of a liquid, its vapour pressure

Increases

The boiling point of a liquid is the temperature at which the vapour pressure

Is equal to the external pressure

The normal boiling point of a liquid is the temperature at which it boils when the external pressure is

1 atm

If the non-volatile impurities contaminate the liquid, its boiling point gets

Elevated

The energy required to vaporize 1 mole of a liquid is known as

Molar heat of vaporization

At 1 atm pressure, the boiling point of water is

100 deg C

The boiling point and molar heat of vaporisation is dependent on

Strength of the inter-molecular forces

Select the incorrect statement from the following options a) Methane and argon have weak dispersion forces so their boiling point is low b) Diethyl ether has a dipole moment, and the dipole-dipole forces account for its moderately high boiling point c) Water and ethanol have strong hydrogen bonding and hence they possess high boiling point d) Mercury has weak metallic bonding which is responsible for its low boiling point

d) Mercury has weak metallic bonding which is responsible for its low boiling point

For a given substance, choose the correct statement

Hfus is smaller than Hvap

The molar heat of vaporisation (Hvap) for water is

40.79 kJ/mol

The analysis of electromagnetic radiation scattered, absorbed or emitted by the molecule is called

Spectroscopy

The energy level with lower energy is called

Ground state energy level

Absorption spectrum results when an electron in an atom undergoes a transition from

Lower energy level to a higher one

The energy of a photon is given by

Select the INCORRECT statement from the following option. a) Emission spectrum results when an electron in an atom undergoes a transition from excited state to the ground state b) In the emission spectrum, transition takes place with the emission of a photon of energy h? c) In the emission spectrum, transition takes place with the absorption of a photon of energy h? d) All of the mentioned

c) In the emission spectrum, transition takes place with the absorption of a photon of energy h?

The spectra can be broadly classified into two categories. They are

Atomic and molecular spectra

In atomic spectroscopy, only electronic transitions are involved.

TRUE

Select the correct statement from the following options. a) Molecular spectra arises from the transition of an electron between the molecular energy levels b) In molecular transitions, electronic, rotational and vibration transitions occurs c) Molecular spectra is more complicated than atomic spectra d) All of the mentioned

All of the mentioned

The necessary condition for absorption spectrum is that

hv should be equal to the energy difference

Spectroscopy deals with the transition that a molecule undergoes on the absorption of suitable radiations determined by quantum mechanical selection rules.

TRUE

(Molecular Spectroscopy) The different types of energies associated with a molecule are __________ a) Electronic energy b) Vibrational energy c) Rotational energy d) All of the mentioned

All of the mentioned

(Molecular Spectroscopy) During the motion, if the center of gravity of molecule changes, the molecule possess ________.

Translational Energy

The correct order of different types of energies is

E el >> E vib >> E rot >> E tr

The region of electromagnetic spectrum for nuclear magnetic resonance is

Radio frequency

Which of the following is an application of molecular spectroscopy? a) Structural investigation b) Basis of understanding of colors c) Study of energetically excited reaction products d) All of the mentioned

All of the mentioned

Select the CORRECT statement from the following option. a) Spectroscopic methods require less time and more amount of sample than classical methods b) Spectroscopic methods require more time and more amount of sample than classical methods c) Spectroscopic methods require less time and less amount of sample than classical methods d) Spectroscopic methods require more time and less amount of sample than classical methods

c) Spectroscopic methods require less time and less amount of sample than classical methods

The results obtained by spectroscopic methods are less reliable, less reproducible and incorrect than classical methods.

FALSE

The transition zone for Raman spectra is

Between vibrational and rotational levels

The criteria for electronic spin resonance is

Presence of unpaired electron in a molecule

Sample recovery is possible after spectroscopic analysis because the sample is not chemically affected.

TRUE

(Electronic Spectroscopy) The electronic spectra in the visible range span is

12500-25000 cm-1

(Electronic spectroscopy) Which of the following transitions are of weak intensities and lie in the visible region? Note: o is sigma a) n --> n* b) o --> o* c) pi --> pi* d) n --> o*

a) n --> n*

(Electronic spectroscopy) Arrange the various electronic transitions in the order of increasing energy.

n --> pi* < pi --> pi* < n --> o* < o --> o*

(Electronic spectroscopy) What is the position of the band of alkanes?

150 nm

(Electronic spectroscopy) Which of the following organic compound shows transition due to conjugation?

Conjugated dienes

Which of the following is not an auxochrome group? a) -OH b) -SH c) -OR d) -O2

d) -O2

Which of the following shift leads to the decreased intensity of absorption?

Hypochromic

Which of the following is an application of electronic spectroscopy? a) Detection of impurities b) Control of purification c) Study of kinetics of the chemical reaction d) All of the mentioned

All of the mentioned

What will be the absorbance if percent T = 80?

0.097

Which of the following is a limitation of the Lambert-Beer's law? a) Scattering of light due to particles b) Fluorescence of sample c) Non-monochromatic radiation d) All of the mentioned

All of the mentioned

Vibrational spectroscopy involves the transitions falling in the spectral range of

400-4000 cm-1

Which of the region of IR spectra appears between (1400-600) cm-1?

Fingerprint region

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

All of the mentioned

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

a) NO

Which of the following cannot show a vibrational absorption spectrum? a) OCS b) H2O c) CO2 d) CH2 = CH2

d) CH2 = CH2

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

Stretching

What is the absorption frequency(cm-1) of -C=N functional group?

1180-1360

Presence of a functional group in a compound can be established by using

IR spectroscopy

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

None of the mentioned

IR spectroscopy helps in detecting the presence of hydrogen bonding.

TRUE

(Nuclear Magnetic resonance) The nuclei with a spin quantum number greater than _______ can exhibit the NMR phenomenon.

0 (zero)

(NMR) The number of different orientations which a magnetic nucleus can take is

2l + 1

Number of NMR signals obtained in CH3COCH3 will be

Propene as well as 2-Butene(cis) will show equal number of signals in their NMR spectra.

FALSE

Select the INCORRECT statement from the following option. a) TMS stands for tetra methyl silane b) All the hydrogen in TMS have the same chemical shift c) TMS has a high boiling point, so it is not easily lost when holding the NMR sample d) TMS is relatively unreactive with most functional groups

c) TMS has a high boiling point, so it is not easily lost when holding the NMR sample

The NMR spectra of the functional isomers of the molecular formula C2H6O show _____ and _____ signals respectively.

1, 3

(NMR) The number of signals in 1-propanol are ____ while those in 2-propanol are ____.

4, 3

For NMR spectrum, carbon tetrachloride and water can be successfully used as a solvent.

TRUE

(NMR) In how many ways -CH3 protons can couple with the protons on adjacent carbon atom relative to the external field.

(NMR) Which of the following is inversely proportional to the chemical shifts positions (delta lower case)? a) Frequency of unknown group of protons b) Frequency of TMS c) Operating frequency of the instrument d) All of the mentioned

c) Operating frequency of the instrument