Free Spectroscopy and Analysis MCQs with Answers

21. The breakdown of molecular ions from natural products gives important information about?

• A. Size
• B. Position
• C. Shape
• D. Structure

Explanation: The breakdown or fragmentation of molecular ions from natural products, typically obtained by techniques such as mass spectrometry, can provide important information about the structure, composition, and identity of the natural product.

22. Chromyl Test is performed to confirm:

• A. Cl− ions
• B. SO4−2 ions
• C. PO4−3 ions
• D. Cr+3 ions

Explanation: Explanation:The chromyl chloride test is performed to detect chloride ions in the qualitative analysis. When any chloride salt for example sodium chloride (NaCl) is heated with acidified potassium dichromate, it gives fumes of chromyl chloride which is used to be in orange-red color. This confirms the presence of chloride ions in the salt.The chromyl test is not used to confirm the presence of sulfate ions (SO4-2). The chromyl test is not used to confirm the presence of phosphate ions (PO4-3). The chromyl test is also not used to confirm the presence of chromium ions (Cr+3).

23. The relative abundance of the isotopes of the elements can be determined by:

• A. Mass Spectrometry
• B. X-rays
• C. Chromatography
• D. Solvent Extraction

Explanation: A is correct as mass spectrometry is a method to differentiate between different isotopes of an element.B is incorrect as X-ray cant be used to differentiate between different isotopes of an element.C is incorrect as chromatography is used to differentiate between different solvents.D is incorrect as solvent extraction is a method to extract a soluble solute from a solution.

24. The type and relative amount of each isotope in an element can be found by:

• A. R spectroscopy
• B. U.V spectroscopy
• C. Mass Spectrometry
• D. N.M.R

Explanation: Mass Spectrometry (MS) is an analytical technique used to measure the mass-to-charge ratio of ions. It provides detailed information about the molecular weight and structure of compounds

25. Which of the following reagents can be used to identify Ni+2 ions in solution?

• A. Ethylenediamine
• B. potassium ferrocyanide
• C. dimethylglyoxime
• D. potassium permanganate

Explanation: When identifying Ni+2 ions, dimethylglyoxime is the reagent of choice. Adding dimethyl glyoxime to a solution of Ni+2 ions along with ammonium hydroxide results in the formation of a bright red precipitate. This distinctive color change indicates the presence of Ni+2 ions. The other options, such as ethylenediamine, potassium ferrocyanide, and potassium permanganate, do not react in a way that specifically identifies Ni+2 ions, making them incorrect choices.

26. The fixing solution used in developing a negative in photography contains:

• A. Hydroquinone
• B. Sodium thiosulphate
• C. Pyfogallal
• D. AgBr

Explanation: Sodium thiosulfate (sodium hyposulfite), Na2S2O3, is used by photographers to fix developed negatives and prints; it acts by dissolving the part of the silver salts coated onto film which remain unchanged by exposure to light. Fixation is commonly achieved by treating the film or paper with a solution of thiosulfate salt. Popular salts are sodium thiosulfate-commonly called hypo-and ammonium thiosulfate-commonly used in modern rapid fixer formulae.

27. Continuous adsorption spectrum is obtained from:

• A. excited atoms
• B. Excited molecules
• C. Ground state molecules
• D. Ground state atoms

Explanation: Excited atoms: When atoms are excited, either by heating or by other means such as electrical discharge, they absorb energy and transition to higher energy levels. As these excited atoms return to their ground state, they emit energy in the form of electromagnetic radiation. The absorption and emission of specific wavelengths of light result in a continuous adsorption spectrum. In summary, a continuous adsorption spectrum is obtained from excited atoms, where the absorption of energy and subsequent emission of light results in a continuous range of wavelengths.

28. The device used for the detection of isotopes is

• A. Mass spectrometer
• B. Cyclotron
• C. Betatron
• D. Reactor

Explanation: The mass spectrometer is a device commonly used for the detection and analysis of isotopes. It separates ions based on their mass-to-charge ratio, allowing for the identification and quantification of different isotopes in a sample.

29. The instrument that is used to determine the weight of a proton as well as a positive ion and is capable of recording its result as the photograph is called:

• A. Mass spectroscope
• B. Atomic spectroscope
• C. Spectrophotographic analyzer
• D. Spectrophotometer

Explanation: A mass spectroscope is an instrument used to determine the weight (mass) of a proton as well as positive ions. It works based on the principle of mass spectrometry, which involves ionizing a sample and separating the ions based on their mass-to-charge ratio. The resulting ion spectrum can be recorded and analyzed.

30. The ring test is shown by compounds having:

• A. Sulphate radical
• B. Chloride radical
• C. Nitrate radical
• D. None of the above

Explanation: The brown ring test is a qualitative analysis technique used to detect the presence of nitrate ions. When a solution containing nitrate ions is treated with freshly prepared ferrous sulfate and then carefully added to concentrated sulfuric acid, a brown ring forms at the interface between the two layers. This indicates the presence of the nitrate radical. Sulphate and chloride radicals do not produce such a ring. The sulphate radical is typically detected by forming a white precipitate with barium chloride, while the chloride radical forms a white precipitate with silver nitrate.