Answer: A. reduction of I2 by SO2 in presence water and by removal of pyridine iodide

Explanation: Karl Fischer titration determines water content by reducing iodine using sulfur dioxide in the presence of water. The removal of pyridine iodide is essential for an accurate and reproducible titration endpoint.

Answer: D. Kinetic energy

Explanation: At a given temperature, the average kinetic energy of molecules in all ideal gases is the same, regardless of their mass. This principle is a cornerstone of the kinetic molecular theory of gases.

Answer: C. Mass to charge ratio

Explanation: In mass spectrometry, ions are separated on the basis of their mass-to-charge ratio (m/z). This ratio is crucial for identifying and quantifying molecules in complex mixtures.

Answer: A. Cascade impactor

Explanation: A cascade impactor is used to determine the particle size distribution of aerosols by separating particles based on their aerodynamic diameters. This method is essential in pharmaceutical and environmental testing.

Answer: B. indirectly proportional

Explanation: Wave number and frequency are inversely related; as frequency increases, wavelength decreases, leading to an indirect proportionality between wave number and frequency. This relationship is key in spectroscopic analysis.

Answer: B. Northen blotting

Explanation: Northern blotting is the technique used for identifying specific RNA molecules. It involves separation by electrophoresis followed by hybridization with labeled probes to detect gene expression levels.

Answer: D. The magnitude of the diffusion current is proportional to concentration of electroactive species

Explanation: In polarography, the diffusion current increases proportionally with the concentration of the electroactive species, making it a valuable technique for quantitative analysis in electrochemistry.

Answer: C. Zero spin

Explanation: Nuclei with an even number of protons and neutrons typically have zero net spin due to complete pairing, resulting in no magnetic moment and simplified nuclear behavior.

Answer: B. Ion transducer

Explanation: Mass spectrometers comprise an inlet system, a mass analyser, and a detector. An ion transducer is not typically a standard component in these instruments.

Answer: D. 18

Explanation: Stearic acid is a saturated fatty acid consisting of 18 carbon atoms. Its linear, unbranched structure contributes to its high melting point and its wide use in industrial, cosmetic, and pharmaceutical applications.

Answer: B. Electron shielding

Explanation: Chemical shifts in NMR spectroscopy arise primarily due to electron shielding. The surrounding electrons reduce the effective magnetic field at the nucleus, resulting in variations in resonance frequencies that are characteristic of different chemical environments.

Answer: C. Isomaltose

Explanation: Isomaltose is classified as a reducing sugar because it possesses a free aldehyde group in its open-chain form, enabling it to participate in redox reactions unlike non-reducing sugars.

Answer: C. Both A and B

Explanation: Radio waves cover a broad range of frequencies from 30 Hz to 300 GHz and corresponding wavelengths from 1 mm to 10,000 km, which are fundamental characteristics in the field of electromagnetic radiation and communications.

Answer: A. Dichlorofluorescein

Explanation: Dichlorofluorescein is used as the indicator in the Fajans method of argentometry. It changes color at the endpoint, allowing precise determination of silver ion concentration in the titration.

Answer: D. Area of each signal

Explanation: In NMR spectroscopy, the integrals represent the area under each resonance peak, which is proportional to the number of nuclei contributing to that signal, thereby providing quantitative structural information.

Answer: C. 1 ppb

Explanation: Cryogenic shims improve magnetic field homogeneity in NMR spectroscopy to as good as 1 part per billion. This enhancement greatly increases spectral resolution and the accuracy of molecular structure determination.

Answer: D. Carbon Dioxide

Explanation: Carbon dioxide is considered an excellent 'green' solvent in supercritical fluid extraction and is also a significant greenhouse gas. Its unique properties make it useful in various environmentally friendly applications.

Answer: A. GC

Explanation: Gas Chromatography (GC) is the method used to detect residual solvents. It separates volatile compounds, ensuring that solvent levels remain within the regulatory limits for safe pharmaceutical products.

Answer: D. None of the above

Explanation: A protophilic solvent is one that can donate hydrogen bonds; however, among the options, none fit this description accurately, making the correct answer 'None of the above.'

Answer: C. Normality

Explanation: Normality is gram equivalent weight per liter of solution, used for acid-base or redox solutions.