Instrumental Methods Flashcards by Super Giggles

Correct order of IR Stretching frequency
Anhydride
Amide
Ketone

Anhydride > Ketone > Amide

Anhydride : RCO-O-CO-R
Amide : RCO-NH2
Ketone : RCOR

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In IR spectrum, a Compound shows strong & broad peak at 3300 cm-1. The band has become sharp & shift to 3600 when diluted. This proves that.

OH Group with intramolecular H bonding
OH group with inter Molecular H Bonding
A terminal alkyne group
OH group present in severely sterically hindered environment

OH group with inter Molecular H Bonding.

On Dilution, intermolecular H bonding strength decreases.

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A carbonyl group will show a sharp dip at about

1700 cm-1

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An alcohol group will show a sharp dip at about

Free OH : 3600
H bonded : 3200 - 3400

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The band that gives the most intense band in IR spectrum for stretching
1. CH
2. NH
3. OH
4. SH

Stretching frequency proportional to dipole moment

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What is the primary measurement in TGA?

A) Temperature change
B) Mass change
C) Heat flow
D) Electrical conductivity

Mass change

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In TGA, the sample is typically heated in:

A) Air
B) Vacuum
C) Inert gas
D) All of the above

All of the above

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TGA can be used to determine:

A) Moisture content in a sample
B) Thermal stability of materials
C) Composition of multi-component systems
D) All of the above

All of the above

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What type of plot is generated in TGA?

A) Mass vs. Temperature
B) Heat flow vs. Time
C) Temperature vs. Time
D) Mass vs. Time

Mass vs. Temperature

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What is one limitation of TGA?

A) Cannot provide compositional information
B) Cannot analyze volatile components
C) Requires large sample sizes
D) Cannot be performed under inert conditions

Cannot provide compositional information

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DTA measures the difference in temperature between the sample and a reference material during:

A) Heating
B) Cooling
C) Both heating and cooling
D) Only during isothermal conditions

Both heating and cooling

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In DTA, an exothermic reaction is indicated by:

A) A peak upwards on the DTA curve
B) A peak downwards on the DTA curve
C) No change in temperature
D) A horizontal line

A peak upwards on the DTA curve

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DTA is primarily used to study:

A) Thermal stability
B) Phase transitions
C) Decomposition temperatures
D) All of the above

All of the above

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What type of materials can be analyzed using DTA?

A) Solid materials only
B) Liquids only
C) Solids, liquids, and gases
D) Gaseous materials only

Solids, liquids, and gases

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Which of the following statements is true about DTA?

A) It provides quantitative data about mass loss.
B) It measures the heat flow into the sample.
C) It is more sensitive than TGA.
D) It can be used to determine thermal conductivity.

It measures the heat flow into the sample.

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Both TGA and DTA can be used to study:

A) Polymer degradation
B) Melting points
C) Oxidation stability
D) All of the above

All of the above

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Which analysis method would be more appropriate for determining the moisture content in a material?

A) TGA
B) DTA
C) Both
D) Neither

TGA

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TGA and DTA can be performed simultaneously in a technique known as:

A) TGA-DTA
B) Thermomechanical analysis (TMA)
C) Simultaneous thermal analysis (STA)
D) Differential scanning calorimetry (DSC)

Simultaneous thermal analysis (STA)

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In TGA, if a sample shows a significant mass loss at a specific temperature range, what could this indicate?

A) Decomposition of volatile components
B) Formation of new phases
C) Melting of crystalline structures
D) All of the above

Decomposition of volatile components

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When interpreting a TGA curve, the onset temperature of a mass loss event can be crucial. What does the onset temperature represent?

A) The maximum rate of weight loss
B) The temperature at which a reaction begins
C) The final temperature of the sample
D) The temperature of phase transition

The temperature at which a reaction begins

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Which of the following is a key difference between TGA and DTA?

A) TGA measures mass change, while DTA measures temperature change.
B) DTA can only analyze solids, while TGA can analyze liquids.
C) TGA provides heat flow data, while DTA does not.
D) DTA requires larger sample sizes than TGA

TGA measures mass change, while DTA measures temperature change.

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In a DTA analysis, if the temperature difference between the sample and reference is measured to be negative during heating, what does this imply?

A) The sample is undergoing an endothermic reaction.
B) The sample is undergoing an exothermic reaction.
C) The sample is at equilibrium with the reference.
D) The reference material is decomposing.

The sample is undergoing an endothermic reaction

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What would be a suitable analytical technique to use in conjunction with TGA for a comprehensive analysis of a polymer sample’s thermal behavior?

A) X-ray diffraction (XRD)
B) Differential Scanning Calorimetry (DSC)
C) Fourier Transform Infrared Spectroscopy (FTIR)
D) Scanning Electron Microscopy (SEM

Differential Scanning Calorimetry (DSC)

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In a DTA curve, the area of an endothermic peak can be related to which of the following?

A) The heat capacity of the sample
B) The enthalpy change of the reaction
C) The rate of cooling
D) The mass of the sample

The enthalpy change of the reaction

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When conducting a TGA analysis, which of the following parameters is most critical for ensuring accurate results? A) The type of gas used in the atmosphere B) The shape of the sample holder C) The cooling rate during analysis D) The size of the sample

The type of gas used in the atmosphere

Which of the following scenarios would most likely result in overlapping peaks in a DTA curve? A) Multiple phase transitions occurring simultaneously B) The sample containing impurities C) High heating rates D) All of the above

All of the above

What is the main advantage of using a simultaneous TGA-DTA system compared to performing TGA and DTA separately? A) Reduced sample preparation time B) Ability to analyze larger samples C) Correlation of mass loss with thermal events in real-time D) Lower operational costs

Correlation of mass loss with thermal events in real-time

If a TGA curve shows a plateau in mass at elevated temperatures, what does this indicate about the sample? A) The sample has completely decomposed. B) The sample has reached thermal equilibrium. C) The sample contains stable residue. D) The sample has absorbed moisture.

The sample contains stable residue.

Which of the following option is appropriate for the TGA and DTA? a) TGA and DTA measures only weight b) TGA measures only weight while DTA measures other effects c) TGA and DTA measures only temperature d) TGA measures only temperature while DTA measures other effects

TGA measures only weight while DTA measures other effects DTA detects effects such as polymorphic transitions, which do not involve changes in weight.

In the schematic DTA sequence having reversible and irreversible changes, starting with the hydrated material, which of the following steps occurs first on heating? a) Esterification b) Methylation c) Rehydration d) Dehydration

Dehydration On cooling, the melt crystallizes and the polymeric change also occur, exothermically on cooling but rehydration does not occur.

On studying the reversible process during DTA which of the following is observed on both heating and cooling? a) Esterification b) Hysteresis c) Methylation d) Carboxylation

Hysteresis

In the application of DTA and DSC which of the following parameters is measured for the glasses? a) Concentration of the glass b) Solubility of the glass c) Cooling temperature d) Transition temperature

Transition temperature

DTA can be used for which of the following process? a) Line positions of the crystals b) Mechanical properties of the crystals c) Phase diagrams d) Catalytic properties of enzymes

Phase diagrams

During DTA (Differential thermal analysis) what kind of reference material is used? a) Chemically active b) Physically active c) Inert d) Having catalytic property

Inert

In DTA, the ___________________ of sample and reference should be______________ until any thermal event take place. Fill up the appropriate options for the two blanks given from the choices given below. a) Concentration, different b) Concentration, same c) Temperature, different d) Temperature, same

Temperature, same the temperature of the sample and reference material should always be same until any thermal event takes place such as melting, decomposition or cage in crystal structure, occurs in the sample, in which case the temperature either lags behind (if endothermic) or leads (if exothermic) the reference temperature.

What is the factor that limits the application of this differential thermal analysis method? a) Huge apparatus b) Insensitivity c) Highly reactive d) Low growth rate

Insensitivity

What is the reading of output when the sample and reference are at same temperature in DTA? a) Negligible b) Zero c) Very high d) Moderate

Zero

Thermal analysis is defined as ___________ a) Measurement of concentration of materials as a function of temperature b) Measurement of solubility of materials as a function of temperature c) Measurement of physical properties as a function of temperature d) Measurement of line positions of crystals as a function of temperature

Measurement of physical properties as a function of temperature

Which of the following method can be used for the measurement of change in weight of the oxysalts? a) Thermoelectric analysis b) Wagner analysis c) Stockbarger analysis d) Thermal analysis

Thermal analysis

In thermogravimetric analysis, the result obtained appear as a __________ a) Continuous chart b) Continuous parabola c) Continuous circular positions d) Discontinuous chart

Continuous chart

What is the range of the rate in ◦Cmin-1 required during the heating process in TGA? a) 1-20 b) 25-50 c) 100-200 d) 150-1000

a) 1-20 C/min

What is the temperature required for the decomposition of CaCO3 in degree Celsius? a) 200 b) 500 c) 900 d) 1200

500

What is the primary purpose of the stationary phase in column chromatography? A) To dissolve the sample B) To separate components based on size C) To interact with the sample and facilitate separation D) To detect the components

To interact with the sample and facilitate separation

n column chromatography, the elution order of compounds depends on: A) Their boiling points B) Their polarity and affinity for the stationary phase C) Their molecular weight D) Their solubility in the mobile phase

Their polarity and affinity for the stationary phase

What type of mobile phase is commonly used in column chromatography? A) Gas B) Liquid C) Solid D) Any of the above

Liquid

Which of the following is a common use of TLC? A) Determining the purity of a compound B) Separating gases C) Analyzing volatile components D) Measuring molecular weights

Determining the purity of a compound

What is a common stationary phase used in TLC? A) Silica gel B) Water C) Sodium chloride D) Methanol

Silica gel

In gas chromatography, what is the mobile phase? A) Liquid B) Solid C) Gas D) Plasma

Gas

What type of detector is commonly used in GC to identify compounds? A) UV-Vis spectrophotometer B) Flame ionization detector (FID) C) Mass spectrometer (MS) D) Refractive index detector (RID)

Flame ionization detector (FID)

What property of the compounds is primarily exploited in GC for separation? A) Solubility B) Molecular weight C) Volatility D) Polarity

Volatility

What is the main advantage of HPLC over traditional liquid chromatography? A) Faster separation times B) Higher resolution and efficiency C) Ability to handle smaller sample sizes D) All of the above

All of the above

In HPLC, what is the role of the pump? A) To heat the mobile phase B) To maintain a constant temperature C) To propel the mobile phase through the column D) To detect the separated compounds

To propel the mobile phase through the column

Which type of detector is frequently used in HPLC? A) Mass spectrometer B) Conductivity detector C) UV-Vis detector D) All of the above

All of the above

Which chromatography technique is most suitable for separating high molecular weight compounds? A) Column chromatography B) Gas chromatography C) Thin layer chromatography D) High-performance liquid chromatography

High-performance liquid chromatography

What is a common application of GC? A) Analyzing environmental samples for pollutants B) Separating amino acids C) Purifying proteins D) Measuring molecular weight

Analyzing environmental samples for pollutants

In HPLC, the stationary phase is typically: A) A gas B) A solid or liquid bonded to a solid C) A mixture of solvents D) A gel

A solid or liquid bonded to a solid

Which of the following factors does NOT affect the resolution in gas chromatography? A) Column length B) Carrier gas flow rate C) Temperature of the column D) Sample color

Sample color

In TLC, how can one enhance the separation of closely related compounds on a stationary phase? A) Increase the mobile phase viscosity B) Use a higher temperature during development C) Change the polarity of the mobile phase D) Reduce the sample size

Change the polarity of the mobile phase

When utilizing gradient elution in HPLC, what is the primary benefit over isocratic elution? A) It reduces solvent consumption. B) It allows for a broader range of compound separations. C) It decreases the analysis time. D) It enhances the detection sensitivity

It allows for a broader range of compound separations.

In gas chromatography, what is the primary advantage of using a capillary column over a packed column? A) Higher sample capacity B) Faster analysis times due to lower resistance C) Increased temperature stability D) Better retention of high molecular weight compounds

Faster analysis times due to lower resistance

What is the significance of using a gradient temperature program in gas chromatography? A) It improves the detection limits. B) It enhances the separation of compounds with varying volatilities. C) It increases the sample throughput. D) It reduces the overall analysis time.

It enhances the separation of compounds with varying volatilities.

In the context of column chromatography, what does the term "void volume" refer to? A) The volume of the mobile phase B) The volume of the stationary phase C) The volume of the column that does not interact with the sample D) The total volume of the column

The volume of the column that does not interact with the sample

In HPLC, what is the purpose of using a guard column? A) To enhance the sensitivity of detection B) To protect the analytical column from contaminants C) To improve separation efficiency D) To provide a secondary separation mechanism

To protect the analytical column from contaminants

Which of the following techniques is best suited for the analysis of volatile organic compounds (VOCs) in environmental samples? A) High-Performance Liquid Chromatography (HPLC) B) Gas Chromatography (GC) C) Thin Layer Chromatography (TLC) D) Ion Chromatography (IC)

Gas Chromatography (GC)

What is a major limitation of TLC compared to other chromatographic methods? A) Limited sensitivity B) Inability to analyze complex mixtures C) Longer analysis times D) Higher operational costs

Limited sensitivity

Chromatography is a physical method that is used to separate and analyse __________ a) Simple mixtures b) Complex mixtures c) Viscous mixtures d) Metals

Complex mixtures

In which type of chromatography, the stationary phase held in a narrow tube and the mobile phase is forced through it under pressure? a) Column chromatography b) Planar chromatography c) Liquid chromatography d) Gas chromatography

Column chromatography

. In chromatography, the stationary phase can be ___________ supported on a solid. a) Solid or liquid b) Liquid or gas c) Solid only d) Liquid only

Solid or liquid

In chromatography, which of the following can the mobile phase be made of? a) Solid or liquid b) Liquid or gas c) Gas only d) Liquid only

Liquid or gas

Which of the following cannot be used as adsorbent in Column adsorption chromatography? a) Magnesium oxide b) Silica gel c) Activated alumina d) Potassium permanganate

Potassium permanganate

Which of the following types of chromatography involves the separation of substances in a mixture over a 0.2mm thick layer of an adsorbent? a) Gas liquid b) Column c) Thin layer d) Paper

Thin layer

Chromatography cannot be used to purify volatile substances. a) True b) False

False

In Column chromatography, the stationary phase is made of _________ and the mobile phase is made of _________ a) Solid, liquid b) Liquid, liquid c) Liquid, gas d) Solid, gas

Solid, liquid

In Thin layer chromatography, the stationary phase is made of _________ and the mobile phase is made of _________ a) Solid, liquid b) Liquid, liquid c) Liquid, gas d) Solid, gas

Solid, liquid

In which of the following type of paper, chromatography does the mobile phase move horizontally over a circular sheet of paper? a) Ascending paper chromatography b) Descending paper chromatography c) Radial paper chromatography d) Ascending – descending chromatography

Radial paper chromatography

Liquid chromatography can be performed in which of the following ways? a) Only in columns b) Only on plane surfaces c) Either in columns or on plane surfaces d) Neither in columns nor on plane surfaces

Either in columns or on plane surfaces

Gas chromatography can be performed in which of the following ways? a) Only in columns b) Only on plane surfaces c) Either in columns or on plane surfaces d) Neither in columns nor on plane surfaces

Only in columns

Thin layer chromatography is A. partition chromatography B. electrical mobility of ionic species C. adsorption chromatography D. none of the above

adsorption chromatography

In gas chromatography, the basis for separation of the components of the volatile material is the difference in A. partition coefficients B. conductivity C. molecular weight D. molarity

partition coefficients

In reverse phase chromatography, the stationary phase is made A. non-polar B. polar C. either non-polar or polar D. none of these

non-polar

Ion exchange chromatography is based on the A. electrostatic attraction B. electrical mobility of ionic species C. adsorption chromatography D. partition chromatography

electrostatic attraction

Which effect results from slow injection of a large sample volume in GC? a) Increased resolution b) Decreased resolution c) Non-linear detector response d) Constant resolution

Decreased resolution

What is the typical internal diameter of fused silica capillary columns in GC? a) 0.2-0.3 mm b) 0.3-0.5 mm c) 0.5-1.0 mm d) 1.0-2.0 mm

0.2-0.3 mm

Which of the following cannot be used as an adsorbent in Column adsorption chromatography? a) Magnesium oxide b) Silica gel c) Activated alumina d) Potassium permanganate

Potassium permanganate

What happens during the ‘elution from the column’ phase in chromatography? a) Components with greatest affinity elute first b) Components with least affinity elute first c) Components elute in a random manner d) Components elute according to their concentration in the mixture

Components with least affinity elute first

In chromatogram, the position of peaks on the time axis can be used to determine which of the following? a) Components of the sample b) Amount of component in the sample c) Column efficiency d) Column resolution

Components of the sample

In chromatogram, the area under the peak can be used to determine which of the following? a) Components of the sample b) Amount of component in the sample c) Column efficiency d) Column resolution

Amount of component in the sample

How is the molar concentration of solute in stationary phase related to molar concentration of solute in the mobile phase? a) Directly proportional b) Inversely proportional c) Equal d) Not related

Directly proportional

If the value of the distribution constant ‘k’ is one, then what could be inferred about the distribution of solute? a) Its distribution in stationary phase is greater b) Its distribution in mobile phase is greater c) It is equally distributed in stationary and mobile phase d) It is distributed in a random manner

It is equally distributed in stationary and mobile phase Cs α Cm Cs = k Cm

The time taken by the analyte after sample injection to reach the detector is called _________ a) Dead time b) Solute migration rate c) Adjusted retention time d) Retention time

Retention time

The time required for a molecule of the mobile phase to pass through the column is called ___________ a) Dead time b) Solute migration rate c) Adjusted retention time d) Retention time

Dead time

Adjusted retention time is the remaining retention time after subtracting __________ from ___________ a) Solute migration rate and retention time b) Retention time and solute migration rate c) Dead time and retention time d) Retention time and dead time

Dead time and retention time Adjusted retention time is the remaining retention time after subtracting dead time from retention time. It affects the effectiveness of the system

Which of the following is the volume of mobile phase required to make a solute band move from the point of injection through the column to the detector? a) Dead volume b) Retention volume c) Void volume d) Adjusted retention volume

Retention volume Retention volume is the volume of mobile phase required to make a solute band move from the point of injection through the column to the detector.

Adjusted retention volume is the remaining retention volume after subtracting ___________ from _____________ a) Solute migration rate and retention volume b) Retention volume and solute migration rate c) Dead volume and retention volume d) Retention volume and dead volume

Dead volume and retention volume Vadjusted retention = Vretention – Vdead

Which of the following is the ratio of the length of column packing to dead time? a) Average linear rate of solute migration b) Average linear rate of mobile migration c) Relative migration rate d) Selectivity factor

Average linear rate of mobile migration

Which of the following is the ratio of a length of column packing to retention time? a) Average linear rate of solute migration b) Average linear rate of mobile migration c) Relative migration rate d) Selectivity factor

Average linear rate of solute migration

Retention distance is the distance between point of injection and minimum peak in the recorder or computer generated chart. a) True b) False

False Retention distance is the distance between point of injection and maximum peak in the recorder. The chart is drawn between time and concentration of the solute.

Retention volume can be obtained by finding the product of which of the following parameters? a) Dead time and total porosity b) Retention time and volumetric flow rate c) Adjusted retention time and volumetric flow rate d) Retention time and total porosity.

Retention time and volumetric flow rate

Which of the following is the distance that the solute moves while undergoing one partition? a) Retention distance b) Distribution constant c) Plate height d) Column packing length

Plate height Plate height is the distance that the solute moves while undergoing one partition. It is expressed in length.

Which of the following conditions will cause the efficiency of the column to increase? a) Plate number becomes greater, plate height becomes smaller b) Plate number becomes smaller, plate height becomes smaller c) Plate number becomes greater, plate height becomes larger d) Plate number becomes greater, plate height becomes larger

Plate number becomes greater, plate height becomes smaller

Which of the following is the expression for Eddy diffusion in the column, if ‘γ’ represents obstruction factor, ‘dp’ represents particle diameter, ‘DM’ represents Solute diffusion co-efficient and ‘λ’ represents function for packing uniformity? a) λ dM b) 2 γ DM c) DM γ d) λ/dM

λ*dM

. Which of the following is the expression for longitudinal diffusion in the column, if ‘γ’ represents obstruction factor, ‘dM’ represents particle diameter, ‘DM’ represents Solute diffusion co-efficient and ‘λ’ represents function for packing uniformity? a) λ dM b) 2 γ DM c) DM γ d) λ/dM

Longitudinal diffusion is given as, B = 2 γ*DM. It is also called axial diffusion.

In gas-liquid chromatography, when films are used in the interior of the capillary column, then what is the value of Eddy diffusion? a) Greater than 1 b) Less than 1 c) Zero d) Less than zero

c) Zero

For an unpacked coated capillary column, the obstruction factor takes which of the following values? a) 0 b) 0.6 c) 1 d) 1.6

1 For an unpacked coated capillary column, the value of the obstruction factor is 1. For a packed column, the value is 0.6.

The solute, while moving in the column is always in equilibrium with both the stationary phase and the mobile phase. a) True b) False

True The solute, while moving in the column is always in equilibrium with both the stationary phase and the mobile phase. But, the two phases will never be in equilibrium with each other.

Base line resolution is achieved when degree of resolution/separation is ______ a) 1 b) 0 c) 0.5 d) 1.5

1.5

Which of the following equations give the expression for plate number, N when ‘tR’ is the adjusted retention time and ‘Wb’ is the width at the base of the peak which is equal to 4 standard deviations. a) 16 tR^2/Wb b) 4 tR^2/Wb c) (4tR/Wb)^2 d) 4 (tR/Wb)^2

N = (4tR/Wb)^2 It is a dimensionless quantity.

It is more difficult to measure the width at half peak height than the base width in the detector output (Column Chromatography) a) True b) False

False The width at half peak height is easier to measure than the base width. Hence, the plate number is calculated at peak height.

For the separation of which of the following substances, Gas-solid chromatography is being used? a) Thermally stable organic components b) Volatile organic components c) Thermally stable inorganic components d) Low molecular weight gaseous species

Low molecular weight gaseous species

Which of the following is not a feature of carrier gas used in gas chromatography? a) It must be chemically inert b) It should be suitable for the detector employed c) It should not be completely pure d) It should be cheap

It should not be completely pure

Which of the following is the disadvantage of hydrogen, which can be used as carrier gas in gas chromatography? a) Dangerous to use b) Expensive c) Reduced sensitivity d) High density

Dangerous to use

Which of the following is the disadvantage of helium, which can be used as carrier gas in gas chromatography? a) Dangerous to use b) Expensive c) Reduced sensitivity d) High density

Expensive Its advantages are that it has low density and it allows greater flow rates.

Which of the following is the disadvantage of nitrogen, which can be used as carrier gas in gas chromatography? a) Dangerous to use b) Expensive c) Reduced sensitivity d) High density

Reduced sensitivity

Slow injection of large samples leads to band broadening and loss of resolution. a) True b) False

True Slow injection of large samples leads to band broadening and loss of resolution. Hence, for desired column efficiency, samples should not be too large.

Which of the following is the commonly used support material for the packed column in gas chromatography? a) Glass b) Metal c) Diatomaceous earth d) Stainless steel

Diatomaceous earth

Which of the following is the disadvantage of coiled or helical shaped packed chromatographic column? a) It cannot be packed uniformly b) It cannot be repacked easily c) It is not compact d) It is not easy to heat it evenly

It cannot be repacked easily It is compact in size and can easily be heated in an even manner.

Which of the following is not an ideal characteristic of a detector used in gas chromatography? a) Linear response to the solutes b) Short response time c) High reliability d) Sensitive to the changes in the flow rate of a carrier gas

Sensitive to the changes in the flow rate of a carrier gas

Which of the following is not a type of detector used in gas chromatography? a) Argon ionisation detector b) Thermal conductivity detector c) UV visible spectrometric detector d) Electron capture detector

UV visible spectrometric detector UV visible spectrometric detector is not used in gas chromatography. It is used in liquid chromatography.

Which of the following detectors have high sensitivity to all organic compounds? a) Sulphur chemiluminescense detector b) Thermionic emission detector c) Flame ionization detector d) Argon ionisation detector

Flame ionization detector

Which of the following detectors is widely used to detect environmental samples like chlorinated pesticides and polychlorinated biphenyls? a) Flame ionization detector b) Thermal conductivity detector c) Argon ionisation detector d) Electron capture detector

Electron capture detector It is highly sensitive to molecules containing functional groups such as halogen and phosphorous.

Which of the following is not the advantage of thermal conductivity detector used in gas chromatography? a) Simple in construction b) High sensitivity c) Large linear dynamic range d) Non-destructive character

High sensitivity

In which of the following detector is the eluent mixed with hydrogen and burned and then mixed with ozone and its intensity is measured? a) Sulphur chemiluminescense detector b) Thermal conductivity detector c) Flame ionization detector d) Electron capture detector

Sulphur chemiluminescense detector

Which of the following detector uses ultraviolet radiation from lamps to produce ionisation of solute molecules? a) Sulphur chemiluminescense detector b) Thermal conductivity detector c) Photo ionization detector d) Electron capture detector

Photo ionization detector

Flame ionisation detector is also known as Katharometer. a) True b) False

False Thermal conductivity detector is known as Katharometer. It uses heated filament as a sensing element and it is placed in the emerging gas stream.

Which of the following detectors has a non-volatile bead of rubidium silicate placed above the flame tip? a) Argon ionisation detector b) Thermionic emission detector c) Flame ionization detector d) Electron capture detector

Thermionic emission detector

. In which of the following detectors, the carrier gas is excited by a radioactive source and the atoms of carrier gas are excited to a metastable state? a) Argon ionisation detector b) Thermionic emission detector c) Flame ionization detector d) Electron capture detector

Argon ionisation detector

Which of the following is not used as a heating element in a Thermal conductivity detector? a) Platinum b) Gold c) Graphite d) Tungsten wire

Graphite Platinum, gold and tungsten wire are used as heating elements.

Electron capture detector is much less susceptible to contamination when nickel is used instead of tritium. a) True b) False

True The sensitivity of nickel is less than that of tritium.

Gas-solid chromatography is based on which of the following processes? a) Partition of the analyte between a gaseous mobile phase and a stationary liquid phase b) Adsorption of gaseous substances on solid surface c) Ion exchange d) Large molecules cannot penetrate through the gel

Adsorption of gaseous substances on solid surface

Which of the following components cannot be retained by gas-liquid columns but can be separated by using gas-solid chromatography? a) Formaldehyde b) Hydrogen sulphide c) Benzene d) Carbon dioxide

Hydrogen sulphide

Which of the following is not an advantage of gas-solid chromatography? a) Increased column life b) Can be used for separation of rare gases c) Leads to semi-permanent retention of the analyte d) Ability to retain some components that cannot be easily retained by other gas chromatography method

Leads to semi-permanent retention of the analyte Gas-solid chromatography leads to semi-permanent retention of the analyte. Hence, it is used for limited applications.

The distribution coefficients of Gas-solid chromatography are greater than that of Gas-liquid chromatography. a) True b) False

True

Which of the following columns can be used in Gas-solid chromatography? a) Open tubular column b) Analytical column c) Separation column d) Guard column

Open tubular column

Which of the following is not an advantage for the conversion of packed columns into wide bore capillaries? a) Longer retention times b) Longer life c) Higher efficiency d) Greater inertness

Longer retention times Wide bore capillary has a shorter retention time. It is an advantage. It is undesirable to have a longer retention time.

Gas-solid chromatography can be used only for separation of certain low molecular weight gaseous species. a) True b) False

True This is because of gas-solid chromatography, semi-permanent retention of analyte only takes place.

Which of the following is a special adsorbent used in gas-solid chromatography? a) Molecular sieves b) Silica gel c) Alumina d) Starch

Molecular sieves

Which of the following properties of molecular sieves make it ideal for exclusion mechanism of separation? a) High thermal stability b) Large inner surface area c) Variable framework charge d) Ability to distinguish materials on the basis of their size

Ability to distinguish materials on the basis of their size

Which of the following will improve the efficiency of the separation process in liquid chromatography? a) Increase in sample size, increase in column diameter b) Reduction in sample size, increase in column diameter c) Increase in sample size, reduction in column diameter d) Reduction in sample size, reduction in column diameter

Reduction in sample size, reduction in column diameter

Which of the following are the practical problems that arise due to the decrease in column diameter? a) Requirement of large particle size and high pressure drop b) Requirement of large particle size and low pressure drop c) Requirement of small particle size and high pressure drop d) Requirement of small particle size and low pressure drop

Requirement of small particle size and high pressure drop

Which of the following is not true about the guard column used in liquid chromatography? a) It filters particles that clog the separation column b) It extends the lifetime of separation column c) It allows particles that cause precipitation upon contact with stationary or mobile phase d) The size of packing varies with the type of protection needed

C. It allows particles that cause precipitation upon contact with stationary or mobile phase Guard column removes particles that cause precipitation upon contact with stationary or mobile phase. It is placed before the separation column.

Which of the following columns are not used in liquid or high performance liquid chromatography? a) Analytical column b) Separation column c) Guard column d) Capillary column

Capillary column Capillary column is used in gas chromatography. Analytical column is also known as a separation column.

Which of the following types of liquid chromatography uses immobilized biochemical as a stationary phase? a) Ion exchange chromatography b) Exclusion chromatography c) Affinity chromatography d) Gel permeation chromatograph

Affinity chromatography It is used to separate one or few solutes from hundreds of unretained solutes.

Which of the following is not true about solvent programming which is done in high performance liquid chromatography? a) It provides unequal bandwidths b) It provides fast overall separation c) It provides maximum resolution d) It provides maximum sensitivity

It provides unequal bandwidths Solvent programming is done to provide equal bandwidths. It provides maximum sensitivity for every solute in the sample.

Which of the following pulse damper takes up some amount of the pulsation energy which is released to provide smooth pressure without pulsations? a) Flexible bellows or compressible gas passed through tee columns b) Flexible inert diaphragm c) Electronic pulse damper d) Electrical pulse damper

Flexible bellows or compressible gas passed through tee columns

Which of the following is not a characteristic of the syringe pump used in high pressure liquid chromatography? a) Pressure capability is high b) Maintenance is frequent c) Limited reservoir capability d) Slight change of flow rate when extremely high pressure compresses the solvent

Maintenance is frequent

Syringe pumps used in High pressure liquid chromatography are most suitable for which of the following columns? a) Capillary columns b) Guard columns c) Short-fast columns d) Small bore columns

Small bore columns

Gravity feed method for solvent delivery is not used with narrow bore columns packed with fine mesh particles. a) True b) False

True This is because they cannot deliver solvent at high pressure.

Which of the following cannot be done to reduce ripple in High pressure liquid chromatography? a) Using bellows b) Using restrictors c) Using long nylon tube between pump and column d) Avoiding the use of the solvent pump

Avoiding the use of the solvent pump

Bulk property detectors used in liquid chromatography does not respond to which of the following properties? a) Refractive index b) Density c) Properties of solutes d) Dielectric constant

Properties of solutes

Which of the following is not a property of a good detector used in liquid chromatography? a) Good sensitivity b) Ability to function in the presence of a large background signal c) Short response time d) Volume of detector must be large

Volume of detector must be large The volume of the detector must be small. If the volume of the detector is large it may lead to band broadening.

Detector selectivity is more important in Liquid chromatography than in Gas chromatography. a) True b) False

true This is because in liquid chromatography, chances of overlapping are higher

Which of the following detectors depend on Snell’s law at the interface between the cell wall and the flowing liquid to deflect the light beam? a) Electrochemical detectors b) Fluorescence detectors c) Refractive index detectors d) Thermal conductivity detectors

Refractive index detectors

Refractive index detectors used in liquid chromatography are not based on which of the following processes? a) Interference b) Refraction c) Reflection d) Absorption

Absorption It depends on reflection, refraction and interference.

Which of the following can not be detected by UV absorption spectra 1. Functional Group 2. Conjugation 3. Optical Isomerism 4. Geometric Isomerism

Optical Isomerism

What is the wavelength range for UV spectrum of light? a) 400 nm – 700 nm b) 700 nm to 1 mm c) 0.01 nm to 10 nm d) 10 nm to 400 nm

10 nm to 400 nm

Which of the following comparison is correct for solvent shift on the n –>π* transition of acetone? a) H20 = CH30H = C2H50H = CHC13 = C6H14 b) H20 > CH30H > C2H50H > CHC13 > C6H14 c) H20 < CH30H < C2H50H < CHC13 < C6H14 d) H20 > CH30H < C2H50H < CHC13 < C6H14

c) H20 < CH30H < C2H50H < CHC13 < C6H14 H-bonding with ground state in n–> π* results in increase in energy gap & decrease in wavelength. And as polar solvents show strong H-bonding. So, the correct option C

What is the correct order of λmax for n –> σ* transition? a) R-OH > R-NH2 > R-SH b) R-OH < R-NH2 < R-SH c) R-OH > R-SH > R-NH2 d) R-OH < R-SH < R-NH2

R-OH < R-NH2 < R-SH

What is the correct order of λmax for n –> π* transition for the R-CN, R-NO2, and R-N=N-R?

R-CN < R-NO2 < R-N=N-R

What is the correct order of λmax for π –> π* transition for the following three compounds? a) R-C=C-R > R2C = CR2 > R-CHO b) R-C=C-R < R2C = CR2 < R-CHO c) R-C=C-R = R2C = CR2 = R-CHO d) R-C=C-R < R2C = CR2 >R-CHO

R-C=C-R < R2C = CR2 < R-CHO

What is the correct order of λmax for n–> π* transition for the following three compounds? a) RCOOH > RCOOR’ > RCONH2 b) RCOOH = RCOOR’ = RCONH2 c) RCOOH = RCOOR’ < RCONH2 d) RCOOH = RCOOR’ > RCONH2

RCOOH = RCOOR’ = RCONH2

Beer Lambert’s law gives the relation between which of the following? a) Reflected radiation and concentration b) Scattered radiation and concentration c) Energy absorption and concentration d) Energy absorption and reflected radiation

Energy absorption and concentration

In which of the following ways, absorption is related to transmittance? a) Absorption is the logarithm of transmittance b) Absorption is the reciprocal of transmittance c) Absorption is the negative logarithm of transmittance d) Absorption is a multiple of transmittance

Absorption is the negative logarithm of transmittance

Which of the following is not a limitation of Beer Lambert’s law, which gives the relation between absorption, thickness and concentration? a) Concentration must be lower b) Radiation must have higher bandwidth c) Radiation source must be monochromatic d) Does not consider factors other than thickness and concentration that affect absorbance

Radiation must have higher bandwidth

Beer’s law states that the intensity of light decreases with respect to ___________ a) Concentration b) Distance c) Composition d) Volume

Concentration

Lambert’s law states that the intensity of light decreases with respect to __________ a) Concentration b) Distance c) Composition d) Volume

Distance

. The representation of Beer Lambert’s law is given as A = abc. If ‘b’ represents distance, ‘c’ represents concentration and ‘A’ represents absorption, what does ‘a’ represent? a) Intensity b) Transmittance c) Absorptivity d) Admittance

Absorptivity

Which of the following is not true about Absorption spectroscopy? a) It involves transmission b) Scattering is kept minimum c) Reflection is kept maximum d) Intensity of radiation leaving the substance is an indication of a concentration

Reflection is kept maximum

Transmittance is given as T = P/Po. If Po is the power incident on the sample, what does P represent? a) Radiant power transmitted by the sample b) Radiant power absorbed by the sample c) Sum of powers absorbed and scattered d) Sum of powers transmitted and reflected

Radiant power transmitted by the sample

What is the unit of absorbance which can be derived from Beer Lambert’s law? a) L mol-1 cm-1 b) L gm-1 cm-1 c) Cm d) No unit

No unit Unit of Absorptivity : L mol-1 cm-1

. What is the unit of molar absorptivity or absorptivity which is used to determine absorbance A in Beer Lambert’s formula? a) L mol-1 cm-1 b) L gm-1 cm-1 c) Cm d) No unit

L mol-1 cm-1

Which of the following is the wave number of near infrared spectrometer? a) 4000 – 200 cm-1 b) 200 – 10 cm-1 c) 12500 – 4000 cm-1 d) 50 – 1000 cm-1

12500 – 4000 cm-1

Which of the following options are correct in terms of wavelength for the different types of IR spectrometer? a) Near IR: 0.8 – 2.5 micro meter b) Mid IR: 0.8 – 2.5 micro meter c) Far IR: 2.5 – 50 micro meter d) Mid IR: 50 – 100 micro meter

a) Near IR: 0.8 – 2.5 micro meter Near IR : 08 -2.5 micrometer : mid IR : 2.5 – 50 micrometer far IR : 50 – 1000 micro meter

Instrumental Methods Flashcards

(173 cards)