Viva-Questions on Instrumental Technique of Analysis 2076
Exam Roll No.=
1. Which one of the following techniques can be used for the detection in a
liquid chromatograph?
a. Ultraviolet absorbance or refractive index measurement.
b. Increase in temperature
c. Ionization in flame
d. Thermal conductivity
2. Considering high performance liquid chromatography, which one of the
following statements is FALSE?
a. HPLC is suitable for the separation and determination of the
nonvolatile (high boiling point) components.
b. The stationary phase could be a liquid or a solid.
c. Columns longer than 50 meters have been used here to
increase the efficiency of separation.
d. High pressure is used here to decrease the retention time and
improve the separation of components.
3. According to Beer’s law for a colored solution, which one of the following
statements is False?
(a) The percent transmission is not directly proportional to the concentration.
(b) The absorbance is directly proportional to the concentration.
(c) The absorbance does not change when the cell path length
(cell thickness) increases.
(d) When the concentration of the unknown sample is higher than the
highest concentration in the calibration range, the sample should
be diluted.
4. Deuterium and tungsten lamps are used as a light source in one of the
following techniques.
(a) Nuclear magnetic resonance spectrophotometers
(b) X-rays diffractometers
(c) Gas chromatograph
(d) Uv/Visible spectrophotometers
5. Which one of the following arrangements for the sequence of the main components
of a Uv/visible spectrophotometer is Correct?
(a) Light source Monochromator Sample cell Detector Readout
(b) Light source Detector Sample cell Monochromator Readout
(c) Light source Sample cell Detector Monochromator Readout
(d) Light source Readout Sample cell Detector Monochromator
6. Considering the electrochmical cells, which one of the following statements is False?
(a) Galvanic cell is that in which a spontaneous chemical reaction takes place
and an electrical energy is produced.
(b) A nonspontaneous chemical reaction is forced to occur in the
electrolysis cell.
(c) The salt bridge is used to allow for the movement of electrons
from the solution of one half cell to the other
(d) The cathode is the electrode at which reduction takes place.
7. which one of the following radiation has the longer wavelength
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Viva-Questions on Instrumental Technique of Analysis 2076
Exam Roll No.=
a- infra red
b- visible
c- x-ray
d- ultra violet
e- gamma rays
8. The energy associated with infra red is enough to make
a- electronic transitions
b- vibrational and rotational transitions
c- a full separation of the electron in the outer shell
d- X-ray fluorescence
e- an electron move from an inner orbital
9. The moisture in an organic substance is determined by
a- potentiometric titration
b- X-ray fluorescence
c- X-ray absorption
d- Karl Fisher titration
e- Measuring the pH of the system
10. The technique used to identify a functional group in an organic molecule
is a- coulometry
b- X-ray fluorescence
c- Infrared spectrometry
d- Karl Fisher titration
e- Conductimetry
11. One part per million is the same as
(a) 1 g/g
(b) 1 mg/kg
(c) 1 ng/mg
(d) All of the above are correct
12. Narrow line spectra are emitted by
(a) hot solids
(b) excited polyatomic molecules
(c) molecules in the ground molecular state
(d) excited atoms
13. What are the dimensions of the molar absorptivity in the Beer's law expression ?
(a) Moles per liter
(b) Liters per mol.centimeter
(c) Grams per mole
(d) Micrograms per square centimeter
14. The region of the electromagnetic spectrum in which the highest
energy photons are observed is the
(a) ultraviolet
(b) infrared
(c) microwave
(d) x-ray
14. An important advantage of a double-beam spectrophotometer over a single-beam
spectrophotometer is that
(a) it permits cancellation of slow variations of the source power
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Viva-Questions on Instrumental Technique of Analysis 2076
Exam Roll No.=
(b) it requires same light source for Uv, Vis, and Infra red radiation
(c) it can be used in conjunction with rapid response detection systems
(d) a greater range of wavelengths can be used
15. Grating is a device used in the spectrophotometer to function as
(a) a light source
(b) a monochromator
(c) a detector
(d) a nebulizer
16. Reversed phase HPLC is the technique in which
(a) stationary phase is solid and mobile phase is liquid.
(b) the stationary phase is made of very fine particles.
(c) the stationary phase is non polar and the mobile phase is relatively polar.
(d) the stationary phase has been silinized with dimethyldichlorosilane.
17. Considering high performance liquid chromatography, which one of the
Following statements is FALSE?
(a) HPLC is suitable for the separation and detrmination of the nonvolatile
species.
(b) The stationary phase used in the HPLC column could be relatively polar or
nonpolar liquid.
(c) The separation efficiency has been increased by decreasing the
particle size of the solid support for the stationary phase.
(d) Very long columns have been used here to increase the effecirncy of
separation.
18. How should the concentration of a colorless sample be determined?
A. Using a UV spectrophotometer
B. Using a VIS spectrophotometer
C. Either a UV or VIS spectrophotometer
D. Using an indicator solution and pH paper
19. The calculation (0.203 + 0.139) / 2.766 should be reported as
(1) 0.1236
(2) 0.123
(3) 0.124
(4) 0.12
20. Which of the following is true?
(1) If an analysis is accurate, it must also be precise.
(2) A precise analytical measurement will always have a small relative standard
deviation.
(3) If an analysis is reproducible, it will be accurate.
(4) None of the above.
21. The wavenumber of a transition is 2000 cm–1. In what part of the
electromagnetic spectrum does this come?
a. Infrared.
b. Radiowave.
c. Microwave.
d. Ultraviolet-visible
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Viva-Questions on Instrumental Technique of Analysis 2076
Exam Roll No.=
22. According to the Beer-Lambert Law, on which of the following does
absorbance not depend?
a. Extinction coefficient of the sample.
b. Colour of the solution.
c. Distance that the light has travelled through the sample.
d. Solution concentration.
23. What is the name of an instrument used to measure the absorbance of a
coloured compound in solution?
a. Colourmeter.
b. Calorimeter.
c. Colorimeter.
d. Coulometer.
24. The dichromate ion absorbs light of wavelength close to 500 nm. Based on
this information, what can you conclude?
a. Solutions of the dichromate ion are colorless.
b. The dichromate ion absorbs within the visible region.
c. The dichromate ion absorbs in the ultraviolet region.
d. The dichromate ion absorbs outside the visible region.
25. Which statement is correct?
a. Wavelength is directly proportional to energy.
b. Wavenumber is directly proportional to wavelength.
c. Wavelength is directly proportional to frequency.
d. Wavenumber is directly proportional to energy.
26. Aqueous KMnO4 solutions are purple. A plot of absorbance against
concentration is:
a. non-linear.
b. linear with a negative gradient.
c. linear with a positive gradient.
d. an exponential curve.
27. The UV/VIS spectroscopy
a. generates colored spectrums
b. can determine the concentration
c. can be used to make light visible
28. At the doubled concentration
a. the wave length of the absorption is different
b. the extinction coefficient is twice as large
c. the extinction is twice as large
29. The units of an IR spectrometer on the X-axis is
a. meter
b. centimeter
c .per centimeter
30. The unit of an NMR spectrum on the X-axis is
a. Hertz
b .ppm
c. cm-1
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