Which of the following statements is incorrect ? a) Isotope dilution was used to

Question

Which of the following statements is incorrect?

a)     Isotope dilution was used to elucidate the biological pathways of photosynthesis.

b)     Neutron activation analysis is an analysis of elements in a sample based on the conversion of stable isotopes to radioactive isotopes by bombarding a sample with neutrons.

c)     A radioactive tracer is a very small amount of a radioactive isotope added to a system used to study the chemical, physical, or biological processes of a system.

d)     Isotope dilution is a technique used to determine the quantity of a substance in a mixture by adding a known amount of an isotope to it.

e)     Isotope dilution may be used to determine the amount of vitamin B12 in food.

Explanation / Answer

(b) Neutron activation analysis is an analysis of elements in a sample based on the conversion of stable isotopes to radioactive isotopes by bombarding a sample with neutrons.

Explanation: In chemistry, neutron activation analysis (NAA) is a nuclear process used for determining the concentrations of elements in a vast amount of materials. NAA allows discrete sampling of elements as it disregards the chemical form of a sample, and focuses solely on its nucleus. The method is based on neutron activation and therefore requires a source of neutrons. The sample is bombarded with neutrons, causing the elements to form radioactive isotopes. The radioactive emissions and radioactive decay paths for each element are well known. Using this information, it is possible to study spectra of the emissions of the radioactive sample, and determine the concentrations of the elements within it. A particular advantage of this technique is that it does not destroy the sample, and thus has been used for analysis of works of art and historical artifacts. NAA can also be used to determine the activity of a radioactive sample.

Related Questions

Navigate

• Browse (All)
• Browse W
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.