Q3(c). Speed distribution curves of argon and helium
[Graph of relative number of molecules against molecular speed, showing Curve 1 and Curve 2, given in the paper.] The graph shows the distribution of molecular speeds for argon and helium at the same temperature. (i) Which curve, 1 or 2, better represents the behaviour of argon? (ii) Which curve represents the gas that effuses more slowly? (iii) Which curve more closely represents the behaviour of fluorine gas? Explain.
Answer in brief
(i) Curve 1 is argon (curve 2 is helium). (ii) Curve 1, argon, effuses more slowly. (iii) Curve 1: F₂ (M = 38.0) has almost the same molar mass as argon (M = 39.95).
Part of VKC Basic
Read the key points and the full model answer with VKC Basic
VKC Basic (₹999 for 6 months) opens every solved answer, the notes, the handbook and the daily answer archive. Every Mains test series includes it.
The full model answer
As written for the answer booklet: the diagram carries the working, the lines stay short. Read here only; it is not offered as a download.
CoversMaxwell–Boltzmann distributionmost probable speedGraham's law of effusionmolecular speedkinetic theory of gases
All parts of Question 3
- 3(a) The least stable of OCN⁻, ONC⁻ and SCN⁻10 marks
- 3(b) Entropy changes when an ice cube melts in the sea at 0 °C10 marks
- 3(c) Speed distribution curves of argon and helium10 marks
- 3(d) Phase diagram of water; critical point and triple point10 marks
- 3(e) Forces on an ion moving through a strong-electrolyte solution10 marks