Q8(b)(i). Sodium solutions in liquid ammonia
A small piece of Na is dissolved in liquid NH₃ and then the solution was made saturated by dissolving more and more Na. In relation to this experiment, answer the following: I. What are the colours of the dilute solution and the concentrated solution? II. What is the composition of the dilute solution? III. How do the molar conductivity and magnetic susceptibility change from dilute to saturated solution? Give possible explanation for the changes.
Model answer
The free solution for 2022 answers questions 1, 2, 4, 5 and 6, the ones picked in its time plan. Question 8 is answered in full in the IFoS Chemistry Paper I, 2021 to 2025 book, with every part of every paper.
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UPSC Indian Forest Service (Main) Chemistry Paper I: Model Answers 2021 to 2025
- All eight questions of each paper, with the question printed above its answer
- Physical chemistry numericals worked with units; inorganic structures drawn
- Topic-wise weightage and a topic-wise index
Coverssodium in liquid ammoniasolvated electronsblue and bronze solutionsmagnetic susceptibilitymolar conductivity
All parts of Question 8
- 8(a) Cooperativity and the Bohr effect10 marks
- 8(b)(i) Sodium solutions in liquid ammonia10 marks
- 8(b)(ii) Reducing reactions of sodium–ammonia5 marks
- 8(c)(i) Equilibrium and relaxation of an isomerisation10 marks
- 8(c)(ii) Zero or negative activation energy5 marks