VKC ScienceChemistry for written exams Telegram

Indian Forest Service (Mains)

Chemistry optional

  • 2 papers
  • 200 marks each
  • 3 h per paper

Paper I covers physical and inorganic chemistry.

Indian Forest Service (Mains), Chemistry optional · 2021 · Paper I

Q6(a). Reversible first-order reaction

Question

Derive the rate equation for kinetics of a reversible reaction of type A ⇌ B, with forward rate constant k₁ and reverse rate constant k₋₁.

Answer in brief

For initial [A] = a, [B] = 0, x = [B]ₜ = xₑ[1 − e^(−(k₁+k₋₁)t)], where xₑ = k₁a/(k₁ + k₋₁).

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.

See what is included Already a member? Sign in

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.

The handwritten model answer pages open with the VKC plan.
Read the whole 2021 solution2021 question paper

Topic notes: rate laws, integrated rate equations and half-lives, with every Civil Services, IFoS and Geo-Scientist PYQ →

Coversreversible first-order reactionopposing reactionsrelaxation to equilibriumrate constantsintegrated rate law

All parts of Question 6