Jawaharlal Nehru Technological University Hyderabad
Jawaharlal Nehru Technological University Hyderabad B.Tech III ANALYTICAL INSTRUMENTATION Previous Question Paper (November/December - 2020 - R16)
Answer any five questions. All questions carry equal marks.
Main
Explain the principle and working of Oxygen analyzer with neat diagram.
Answer
The paramagnetic oxygen analyzer operates on the principle that oxygen is strongly paramagnetic, meaning it is attracted to a magnetic field, unlike most other common gases which are diamagnetic. In the Pauling (dumb-bell) type analyzer, a test body consisting of two nitrogen-filled glass spheres is suspended in a non-uniform magnetic field. When oxygen enters the sample chamber, it is attracted to the regions of highest magnetic field intensity, exerting a torque on the test body. This torque is proportional to the partial pressure of oxygen in the mixture. The displacement of the test body is measured either by a light beam reflected from a mirror attached to the suspension or by an electromagnetic feedback system that restores the test body to its null position. The current required to maintain this null position serves as a direct, linear measure of oxygen concentration.
The absorption coefficient of a glycogen-iodine complex is 0.20 at the light of 450 nm. What is the concentration when the transmission is 40 % in a cuvette of 2 cm?
Answer
To find the concentration, we use the Beer-Lambert Law, expressed as:
where A is absorbance, ε is the absorption coefficient, c is the concentration, and l is the path length (2 cm).
- Convert transmittance (T) to absorbance (A): A = -log₁₀(T) = -log₁₀(0.40) ≈ 0.3979.
- Rearrange the formula to solve for concentration: c = A / (ε × l).
- Substitute the given values: c = 0.3979 / (0.20 × 2).
- Calculate the result: c = 0.3979 / 0.40 = 0.99475.
The concentration of the glycogen-iodine complex is approximately 0.995 units.
With a suitable diagram explain the construction and working principle of thermal conductivity analyzer.
Answer
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Derive an equation for Beers Lambert law.
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Explain the working of a Thermionic emission detector used in Gas Chromatography.
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Compare the advantages and disadvantages of paramagnetic oxygen analyzer.
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With relevant diagram explain the construction and working of High-performance liquid chromatography.
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Explain flame ionization detector used in gas chromatography.
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Explain the sources and detectors used for IR spectrometer with neat diagram.
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Explain the different types of monochromator used for VIS spectrometers.
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With the help of neat diagram explain the construction and working of single and double beam instruments.
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Define Spectrometer. Also, specify the classification of IR region of spectrometer.
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With help of neat diagram explain the construction and working of Atomic absorption spectrometer.
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Explain the construction and working of hollow cathode lamp.
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What are mass spectrometers? Describe magnetic deflection mass spectrometers.
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With the help of neat diagram explain how radiation can be counted using a proportional counter.
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