Q. In UV-Vis spectroscopy, what does the Beer-Lambert law relate?
A.Wavelength and energy
B.Absorbance and concentration
C.Frequency and intensity
D.Temperature and pressure
Solution
The Beer-Lambert law relates absorbance to concentration, indicating that absorbance increases linearly with concentration of the absorbing species.
Correct Answer: B — Absorbance and concentration
Q. What does the peak position in an IR spectrum indicate?
A.Concentration of the sample
B.Molecular weight of the compound
C.Type of functional groups present
D.Purity of the sample
Solution
The peak position in an IR spectrum corresponds to specific functional groups, allowing identification of the types of bonds present in the molecule.
Correct Answer: C — Type of functional groups present
Q. What is a common use of UV-Vis spectroscopy in environmental analysis?
A.Measuring soil pH
B.Detecting heavy metals
C.Analyzing water quality
D.Identifying microorganisms
Solution
UV-Vis spectroscopy is frequently used to analyze water quality by measuring the absorbance of pollutants and contaminants.
Correct Answer: C — Analyzing water quality
Q. What is the main advantage of using FTIR over traditional IR spectroscopy?
A.Higher resolution
B.Faster data acquisition
C.Lower cost
D.Simpler sample preparation
Solution
FTIR (Fourier Transform Infrared) spectroscopy offers higher resolution and faster data acquisition compared to traditional dispersive IR spectroscopy.
Correct Answer: B — Faster data acquisition
Q. What is the primary application of UV-Vis spectroscopy in analytical chemistry?
A.Determining molecular weight
B.Identifying functional groups
C.Quantifying concentrations of analytes
D.Separating mixtures
Solution
UV-Vis spectroscopy is primarily used to quantify the concentration of analytes in solution based on their absorbance at specific wavelengths.
Correct Answer: C — Quantifying concentrations of analytes
Q. What type of information can be obtained from a UV-Vis spectrum?
A.Molecular structure
B.Concentration of ions
C.Presence of functional groups
D.All of the above
Solution
A UV-Vis spectrum can provide information about molecular structure, concentration of absorbing species, and presence of functional groups based on absorbance patterns.
Correct Answer: D — All of the above
Q. Which of the following compounds would you expect to absorb UV light?
A.Alkanes
B.Aromatic compounds
C.Alcohols
D.Carboxylic acids
Solution
Aromatic compounds have delocalized π electrons that can absorb UV light, while alkanes and alcohols do not have such electronic transitions.
Correct Answer: B — Aromatic compounds
Q. Which of the following is a common application of UV-Vis spectroscopy in the pharmaceutical industry?
A.Determining pH of solutions
B.Analyzing drug stability
C.Measuring melting points
D.Identifying impurities
Solution
UV-Vis spectroscopy is commonly used to analyze drug stability by monitoring changes in absorbance over time.
Correct Answer: B — Analyzing drug stability
Q. Which type of sample is most suitable for analysis by IR spectroscopy?
A.Gaseous samples
B.Solid samples only
C.Liquid samples only
D.All of the above
Solution
IR spectroscopy can analyze gaseous, liquid, and solid samples, making it versatile for various types of materials.
