Chemical Engineering Optional


This post is intended to help the people who have done graduation in Chemical Engineering to know the various aspects of taking up the subject as one of the two optional in UPSC IFS examination. I graduated in Chemical engineering and after looking at papers this optional was natural choice for me. I got 248/400 marks in 2017 exam. I will also detail out the strategy and sources for each topic.

1. Why Chemical Engineering as optional?

If you have studied Chemical engg, even a bit seriously during college, it would be easier to pick, especially given the fact that the level of question paper is of moderate difficulty.

For forest service, we have to choose two optional subjects while for civil service only one is required. So if you already have an optional common, the choice of other one for IFS is not difficult as one can go with Forestry which is most taken subject. Forestry is also coverable in 2 month span quite easily. However if you have studied Chemical Engg well (even if its difficult to recall now) and can give little more time 2 months are well enough to give you high rewards.

The other big reason is, questions are mostly repeated, so preparing last 15 years papers would cover a bulk of content. The numericals are not difficult and if one does some practice from standard books it should be easily doable.

2. How to see if Chemical Engineering is right optional for you?

I picked up the past few years papers and had a glance at the questions. Though I couldn’t answer them at that moment but it was like I knew for each question where I had read from in college. I easily could know the level with respect to what I studied in college. This made me confident that if I give a month I could cover this while it would be difficult if I have to read a new subject such as forestry from scratch.

So, one can take Chemical Engineering as optional irrespective of the other optional and can prepare it in 1-2 months. Take a look at PYQ and see the level for yourself and as most of you would judge it’s pretty moderate.


My Strategy

I had opted for chemical engineering along with Mathematics. So I didn’t had the luxury of time, however I made it priority for 45 days.

I referred the standard books from my college days. However while reading each topic, I first made a list of questions from that topic asked in 2000-2016 and identified the areas I needed to cover.

Thereafter I referred standard books and read & prepared notes simultaneously. Whatever the questions were not covered from books I used Google and prepared their answers.

I had benefitted immensely from the guidance I got from Arsalan (IFS Rank 8 – 2015) and Mridul Jaiswal (IFS 2014) on Chemical Engg.

Below I will list out topic wise strategy, and some comments:

Paper – 1

1. Fluid and Particle Dynamics

Main source: Unit Operations of Chemical Engineering – McCabe, Smith and Harroit.

I read the chapter 3rd to chapter 9th and 28-29th fully except the one on compressible fluids. There only basic definitions and numbers would do (first 2-3 pages).

2. Mass Transfer 

Source: Unit Operations of Chemical Engineering

I also referred NPTEL course by Prof. B. Mandal from IIT Guwahati. Understanding the concepts should be the focus. The chapters in books have lot of details all is not to be read. The PYQ should act as pointers. But try to remember formulas frequently asked. Also pay attention to the numericals here. For the Design of equipment subtopic, do some Googling about equipment asked in PYQ.

3. Heat Transfer

Source: Unit Operations of Chemical Engineering + NPTEL Course on Heat Transfer by Prof Anil Verma.

Section B

4. Novel Separation Techniques

I didn’t covered all the techniques. However some techniques can be covered from “Membrane Separation Process” chapter of McCabe and Smith. While for others I referred a “Membrane Separation Process” by Kaushik Nath. (Read only few topics).

5. Process Equipment Design

Source: Pressure Vessel Design Manual by Dennis Moss.

Prepare limited vessels and heads. Also understand and remember the formulas well. I couldn’t remember a formula and missed on a simple 20 mark numerical due to which I had to attempt a theoretical question. But since I have read this topic in detailed during graduation and revised it also, I could attempt that but numericals is always better especially if it’s simple formula based.

6. Process Dynamics and Control

Source: Referred multiple NPTEL courses on this topic and the book Luyben. + Stephanopolous (I read this during college. Referred only for understanding few concepts)

In this topic one very vast area is of instrumentation where lot of instruments are asked in PYQ. Prepare a list and see their working along with schematic diagram. No need to go into much detail.

Paper 2

Section A

1. Material and Energy Balances

Source: Elementary Principles of Chemical Processes by Richard Felder.

Simple topic. Do some numericals.

2. Chemical Engineering Thermodynamics

Source: Book by Smith,Van Ness and Abbott

3. Chemical Reaction Engineering

Source: Octave Levenspiel

Focus on derivations. Also while doing numericals, if time paucity is there no need to derive the formula. But if it’s a 15-20 marks numerical based on simple formulas, it’s better to derive if you have time.

Section B

4. Chemical Technology 

Source: Chemical Process Industries by R. Norris Shreve

This topic is probably the most theoretical, time consuming and “dirty” topic (:P). If you face time crunch leave it or prepare selectively. However if you have time, prepare the topic thoroughly. I prepared it entirely and the best source is Shreve. My Strategy for this topic was little different. As I had less time, but I didn’t wanted to miss out  this, I prepared the notes on each process industry/chemical in sllyabus/PYQ in first iteration without thinking and remembering much. I made diagrams, basic principles and some 1-2 other key points about each process. And then in subsequent revisions I tried to memorise these notes.

5. Environmental Engineering and Safety

Source: For laws and acts – I referred original documents (Water, Air poluttion acts, EPA 1986 – MoEFCC website, FCA)

For generic topics like GHG, GWP, Ozone depletion, Acid rain I prepared the details asked in PYQ and some additional details from Wikipedia articles of these.

For pollution and their control strategies I read the NPTEL course on Environmental Engg (web) by IIT Roorkee. Also, for pollution control equipments principle, diagram, drawbacks, comparisons etc are enough. Much mathematical expressions are not desired.

For HAZOP, HAZAN, fire + safety – refer Plant Design and Economics for Chemical engineers (Timmerhaus) chapter 3. But do selective reading. Also refer internet for some more details about HAZOP and HAZAN. Remember the keywords.

6. Process Engineering Economics

Source: – Timmerhaus.

Understand the concepts and remember the definitions. Very very selective reading is required. Total pages to be read would be around 8-10 pages from above book.

Plant location and Plant layout including piping I prepared from whatever sources I got from Google.

To conclude, the guiding pointers should be the PYQ and the sllyabus. Also most of the numericals in PYQ are seen to be solved examples from above books so target those.

In the next post I will list out few points about attempting the paper and the presentation.

Thank you 🙂




10 thoughts on “Chemical Engineering Optional”

  1. Thanks for sharing important points.
    Proud of you Mr.Vineet kumar ji
    you have cleared this examination in First attempt only without any coaching or any other outside help.
    From the very beginning, You were purely wanted to go for IFS, you did not choose Civil services as u had option. We all know you will do great work in this service and still you are doing. You are true inspiration for all of us.

    Liked by 1 person

  2. Dear sir ,
    You cleared this exam while working , sir can you tell us how you managed both , and for qualifying mains you about to score more marks and can you share your strategy to get more marks in prelims. Since you was a working professional while preparing had u read all NCERT books or standard books with some strategy?


    1. For Working professionals, strategy has to be customized for everyone. Keep some following points in mind:

      1. Utilize free time in between in office on reading and revising. (Like finishing newspaper, reading articles etc.)
      2. Use online note making (I used Evernote) & note the things you study in office time.
      3. Answer writing can be done at home.
      4. Try to give undisturbed 3-4 hours everyday for optional during morning (before office) or after it.
      5. For prelims, finish the basic books as you get time at home. While doing so you can make notes, which you can revise in office time.
      6. Also for working professionals it is important to keep everything read well noted so that it can be accessed anywhere anytime if needed.
      7. Lastly, personally, sometimes when I would not be able to study books, I would see the syllabus topics and read articles on them from EPW, Frontline and any other online magazines. (But this is after basic books only).

      Above points I could think from my journey.


    1. For Indian Forest Service (IFS) we have to study:

      1. Prelims syllabus – same for CSE and IFS
      2. Mains – General Studies – Not that much for IFS. You can manage with Prelims + current affairs.
      – Optionals – CSE has 1 optional while IFS has 2. So you have to prepare Chemical engineering + 1 more. (I had Chemical + Mathematics). But remember, Chemical optional is not there in CSE.


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