Q5(c). Blood volume by ²⁴Na isotope dilution
A small amount of a solution containing ²⁴Na (t½ = 15 hours) is injected into the bloodstream of a man. The initial activity is 2 × 10³ counts second⁻¹. The activity of 1 cm³ of blood sample taken from the man after 5 hours is 16 counts minute⁻¹. Find the total volume of blood of the man.
Model answer
The free solution for 2025 answers questions 1, 3, 4, 6, 9 and 10, the ones picked in its time plan. Question 5 is answered in full in the Geo-Scientist Chemistry Paper I, 2021 to 2025 book, with every part of every paper.
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UPSC Combined Geo-Scientist (Main) Chemistry Paper I: Model Answers 2021 to 2025
- All eleven questions of each paper, with the question printed above its answer
- Titration, gravimetric and nuclear numericals worked with units; structures drawn
- Topic-wise weightage and a topic-wise index
Coversisotope dilutionsodium-24radioactive tracerhalf-lifeblood volume
All parts of Question 5
- 5(a) Structure and geometry of four species10 marks
- 5(b) Ligand field strength of four Cr(III) complexes10 marks
- 5(c) Blood volume by ²⁴Na isotope dilution10 marks