Q12(a). Gas left in an evacuated flask; pressure after adding N₂
A flask of 4 dm³ capacity contains O₂ at 101.325 kPa and 298 K. The gas pressure is reduced to 0.10 Pa by attaching the flask to a pump. Assuming ideal behaviour, answer the following: (i) What will be the volume of the gas which is left behind? (ii) What amount of O₂ and the corresponding number of molecules are left behind in the flask? (iii) If now 2 g of N₂ is introduced, what will be the pressure of the flask?
Model answer
The free solution for 2024 answers questions 1, 2, 3, 4, 5, 8, 9, 13, 14 and 15, the ones picked in its time plan. Question 12 is answered in full in the Geo-Scientist Chemistry Paper II, 2021 to 2025 book, with every part of every paper.
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UPSC Combined Geo-Scientist (Main) Chemistry Paper II: Model Answers 2021 to 2025
- All fifteen questions of each paper, with the question printed above its answer
- Numericals worked from formula to result with units; graphs with labelled axes
- Topic-wise weightage and a topic-wise index
Coversideal gas equationpV = nRTDalton's law of partial pressuresnumber of moleculesgas pressure
All parts of Question 12
- 12(a) Gas left in an evacuated flask; pressure after adding N₂10 marks
- 12(b) Potential of a silver electrode in saturated silver iodide10 marks