BCHCT 133 Question Paper December 2025 — IGNOU BSCG / BSCBCH Chemical Energetics, Equilibria and Functional Group Organic Chemistry–I

If you are preparing for IGNOU BCHCT-133, this is the actual BCHCT 133 Question Paper December 2025. The exam covers thermodynamics, entropy, Gibbs energy, chemical equilibrium, and functional group organic chemistry. It mixes numerical problems with theory and reaction-based questions. Having a solved version helps you understand exactly what IGNOU expects. This paper is relevant for BSCG and BSCBCH students aiming to score well in their term-end exam.

Download Now — Get BCHCT–133 Solved Question Paper December 2025 IGNOU

Stop guessing what to write. The IGNOU BCHCT-133 question paper from December 2025 is now available with solved answers. Whether you need help with enthalpy calculations, equilibrium constants, or organic reaction mechanisms, the solved paper walks you through each answer clearly. Reach out to the Unnati Education team today and get your copy delivered quickly. Students who study from solved papers consistently perform better in IGNOU term-end exams.

What is BCHCT 133 Question Paper December 2025?

The BCHCT-133 December 2025 question paper is a 50-mark, two-part IGNOU term-end exam covering Chemical Energetics, Equilibria, and Functional Group Organic Chemistry-I for BSCG and BSCBCH students.

This paper was held in December 2025 under the official IGNOU Term-End Examination schedule. Part A focuses on thermodynamics and equilibrium. Part B covers organic chemistry mechanisms and reactions. Each part carries 25 marks and requires students to attempt any five questions.

About IGNOU BCHCT–133 — Chemical Energetics, Equilibria and Functional Group Organic Chemistry–I

BCHCT-133 is one of the core chemistry courses in the IGNOU BSCG programme. It builds your understanding of how energy moves in chemical reactions, what drives spontaneous processes, and how molecules behave in equilibrium. Topics include internal energy, entropy, Gibbs energy, equilibrium constants, chemical potential, acid-base chemistry, hydrolysis, and solubility. The organic chemistry section covers naming conventions, aromaticity, electrophiles, elimination mechanisms, and aromatic substitution. At Unnati Education, our academic writers are well-versed in this subject and structure answers the way IGNOU examiners expect them.

BCHCT 133 Question Paper December 2025 — Exam Pattern and Marks Breakdown

The BCHCT-133 December 2025 question paper is a two-hour exam carrying 50 marks total. Part A is titled Chemical Energetics and Equilibria, and Part B is Functional Group Organic Chemistry-I. Each part carries 25 marks. Students must attempt any five questions from seven options in each part. Questions are a mix of 2-mark and 3-mark sub-parts. There are no multiple choice questions. Every answer requires either a written explanation, a derivation, or a numerical solution.

All Questions — BCHCT 133 Question Paper December 2025 IGNOU

You can see the complete paper above. Here are all the questions exactly as printed.

Part A — Chemical Energetics and Equilibria

Note: Attempt any five questions from Question Nos. 1 to 7.

(a) What are intensive variables? Identify intensive variables from the following properties: (i) Volume (ii) Refractive index (iii) Temperature (b) Derive a relationship between the temperature and volume for an adiabatic process.

(a) Show that the heat absorbed by a system at constant volume is equal to increase in internal energy of the system. (b) The reaction of cyanamide, NH2CN(s) with dioxygen was carried out in a bomb calorimeter, and ΔU was found to be –742.7 kJ mol–1 at 298 K. Calculate the enthalpy change for the reaction at 298 K: NH2CN(g) + 3/2 O2(g) → N2(g) + CO2(g) + H2O(l)

(a) What are spontaneous reactions? Give criteria for spontaneity of a reaction in terms of (i) entropy, and (ii) Gibbs energy. (b) The enthalpy change for the following reaction is determined to be 131.28 kJ mol–1 at 298 K: C(graphite) + H2O(g) → CO(g) + H2(g) Calculate the enthalpy change for the reaction at 100ºC. The Cpº (JK–1 mol–1) values are given as: C(graphite) = 8.53; H2O(g) = 33.58; CO(g) = 29.12; H2(g) = 28.82. Assume the heat capacity values to be temperature independent in the range.

(a) Write an equilibrium constant expression for each of the following chemical reactions: (i) 4NO2(g) + O2(g) + 2H2O(g) ⇌ 4HNO3(g) (ii) CH4(g) + H2O(g) ⇌ CO(g) + 3H2(g) (b) Calculate the equilibrium constant Kp and Kc for the reaction: CO(g) + 1/2 O2(g) ⇌ CO2(g) Given that the partial pressure of various gases at equilibrium in a vessel at 3000 K are: PCO = 0.4 atm., PCO2 = 0.6 atm., PO2 = 0.2 atm.

(a) Define chemical potential and give its significance. (b) At a pressure of 1 bar, water undergoes fusion at 273.1 K. Write the equation for the process. Calculate the entropy of fusion of water if the molar enthalpy of fusion of water is found to be 6.02 kJ mol–1.

(a) In the following reactions, label each species as an acid or a base. Also, identify the conjugate and acid-base pairs in these reactions: (i) HSO4–(aq) + NH3(aq) ⇌ SO42–(aq) + NH4+(aq) (ii) HPO42–(aq) + NH4+(aq) ⇌ H2PO4–(aq) + NH3(aq) (b) Calculate the degree of hydrolysis of 0.1 M aqueous solution of sodium acetate at 298 K. Given: Ka(CH3COOH) = 1.8 × 10–5.

(a) What is common ion effect? Explain with the help of a suitable example. (b) For PbCl2, ksp = 3.2 × 10–5. Determine the maximum amount of PbCl2 (in g) that will dissolve in 250 cm3 of water at 25ºC. Given: Molar mass of PbCl2 = 278 g/mol.

Part B — Functional Group Organic Chemistry–I

Note: Attempt any five questions from Question Nos. 8 to 14.

(a) Give IUPAC and common name of C6H5CH2Cl. (b) State Huckel's rule. Which of the following is aromatic? [Structures as shown in the paper] (c) What are electrophiles? Give the structures of two electrophiles.

(a) Explain why t-butyl alcohol undergoes elimination reaction by E1 and n-butyl alcohol by E2 mechanism. (b) Give two examples of o-, p-directing groups in electrophilic aromatic substitution reaction.

Complete any five of the following reactions: (i) C6H5N2+Cl– → (warm, H2O) (ii) CH2(OH)–CH2(OH) + HOOC–C6H4–COOH → (Polymerisation) (iii) RCOCl → (H2/Pd, BaSO4) (iv) C6H5–COCH3 → (i) NH2NH2.HCl (ii) Base (v) p-diethylbenzene → (air, Co[III] salt) (vi) Toluene + Cl2 →

How is benzene converted to acetophenone? Give the specific name of the reaction, its mechanism and one catalyst that is used in this reaction.

Complete any five of the following reactions: (i) Isopropylbenzene → (air, oxidation) (ii) RCHO + (CH2COOEt)2 → (iii) RO–Na+ + R'Cl → (iv) RCOOH + R'–OH → (H+) (v) 2CH3CHO → (dil NaOH) (vi) Phenol + CHCl3 → (–OH)

Explain any five of the following: (i) Why is benzene not used in undergraduate labs? (ii) Role of conc. sulphuric acid in the nitration of benzene. (iii) Hybridisation of carbon attached to –Cl in CH2=CH–Cl. (iv) Role of crown ethers in chemistry. (v) A common laboratory test for aldehydes and ketones. (vi) Why are phenols acidic in nature?

Explain in short any two of the following: (i) Why do phenolphthalein show different colours in acidic and alkaline medium? (ii) Why is –Cl in C6H5Cl difficult to be substituted by a nucleophile as compared to that in (CH3)3CCl? (iii) Why CH3CHO undergoes base catalysed Aldol condensation but not HCHO?

BCHCT 133 Question Paper December 2025 — Syllabus Topics Covered

This paper covers all the major areas of the BCHCT-133 syllabus. In thermodynamics, expect questions on intensive variables, internal energy, adiabatic processes, and enthalpy calculations using Kirchhoff's law. Entropy and Gibbs energy appear through spontaneity criteria and fusion problems. Equilibrium topics include Kp, Kc expressions, and chemical potential. Acid-base chemistry involves conjugate pairs, hydrolysis, and the common ion effect. The organic section tests aromaticity, IUPAC naming, E1 and E2 mechanisms, Friedel-Crafts reactions, aldol condensation, and functional group transformations.

Sample Answer Preview — BCHCT 133 Chemical Energetics Solved Question Paper

Take Question 3(a) as an example. Spontaneous reactions are those that occur on their own without continuous external energy input. In terms of entropy, a reaction is spontaneous if the total entropy of the universe increases. In terms of Gibbs energy, a reaction is spontaneous when the change in Gibbs energy is negative at constant temperature and pressure. This connects both entropy and enthalpy into one practical criterion. Our BCHCT-133 solved question paper covers every such answer with clear reasoning, correct formula application, and proper IGNOU format.

How to Write High-Scoring Answers in BCHCT 133 Question Paper December 2025

For numerical questions, always write the given data first, then the formula, then the substitution, and finally the result with units. IGNOU examiners appreciate structured working. For derivations like the adiabatic temperature-volume relation, start from the first law and work step by step. In organic chemistry, draw the mechanism wherever possible. Even a rough structural diagram earns marks. For theory questions, keep answers focused and use chemical equations to support your explanation. Do not write vague paragraphs. IGNOU rewards precision.

Who Should Use This BCHCT–133 Solved Question Paper December 2025?

This solved paper is most useful for IGNOU BSCG and BSCBCH students who are appearing in BCHCT-133 or planning to appear in a future attempt. It also helps students who missed a session and want to understand what types of questions are asked. If you find the official study material dense or hard to follow, the solved paper gives you a clearer path. Chemistry learners preparing independently will also benefit from seeing how answers are structured according to IGNOU's expectations.

Why This Is Better Than Free BCHCT–133 December 2025 Question Paper PDFs and Telegram Files

Most free PDFs floating around on Telegram contain only the question paper with no answers, or worse, incorrect solutions copied from random sources. Here's the important part: an unsolved paper does not help you when you are stuck on a numerical or unsure how to structure a mechanism answer. The Unnati Education solved paper gives you verified answers, clear stepwise solutions, and explanations that match IGNOU's marking style. That difference matters when you are preparing a week before your exam.

Student Reviews — BCHCT–133 Solved Question Paper by Unnati Education

Priya from Delhi wrote: "I had no idea how to approach the Kp and Kc numerical in BCHCT-133. The solved paper made it so clear. Cleared my exam in December 2025."

Rahul from Lucknow shared: "I downloaded a free PDF from Telegram but the answers were wrong. Unnati's solved paper was the better choice. Every answer matched the IGNOU pattern."

Sneha from Pune said: "The organic chemistry section was my weak point. The mechanism explanations in this solved paper really helped me understand E1 and E2 properly."

How to Get the BCHCT–133 Solved Question Paper December 2025

Getting your copy is simple. Visit the Unnati Education website or contact the team directly through WhatsApp. Share your requirement mentioning BCHCT-133 December 2025 solved paper. The team will confirm availability and send you the paper promptly. Payment options are flexible and student-friendly. Most students receive their copy within a few hours of placing the request.

Frequently Asked Questions — BCHCT 133 Question Paper December 2025 IGNOU

What topics are covered in BCHCT-133 December 2025? The paper covers thermodynamics including internal energy, enthalpy, entropy, and Gibbs energy. It also includes chemical equilibrium with Kp and Kc calculations, acid-base chemistry, hydrolysis, solubility product, and organic chemistry covering aromaticity, IUPAC naming, reaction mechanisms, and functional group transformations. Both conceptual theory and numerical problems appear throughout both sections of the exam.

How many marks does BCHCT-133 carry and what is the exam pattern? BCHCT-133 carries 50 marks in total. The exam is divided into Part A covering Chemical Energetics and Equilibria for 25 marks, and Part B covering Functional Group Organic Chemistry for 25 marks. Students must attempt any five questions from seven in each part. The duration of the exam is two hours and questions include sub-parts carrying 2 and 3 marks each.

Is the BCHCT-133 solved paper useful for future attempts as well? Yes, absolutely. IGNOU often repeats similar question types across sessions. Understanding how to solve a numerical on enthalpy using Kirchhoff's law or how to write an E1 mechanism correctly will help you in future attempts too. The concepts tested in December 2025 are drawn from the same syllabus, so the solved paper remains relevant and useful beyond just one exam cycle.

How is the Unnati Education solved paper different from what I find free online? Free resources online usually contain only the question paper without solutions, or they carry unverified answers that may mislead you. Unnati Education's solved paper includes step-by-step solutions written by subject-experienced academic writers who understand the IGNOU examination format. Every numerical is solved with proper working, and every theory answer is written to match the length and structure that IGNOU examiners expect.

About Unnati Education — IGNOU Study Material Experts

Unnati Education has been supporting IGNOU students across programmes for several years. The team includes academic content writers with subject-level expertise in science, humanities, and commerce. All solved papers are prepared with reference to IGNOU's official syllabi and past paper trends. The platform is trusted by students from BSCG, BSCBCH, BA, BCOM, and several other IGNOU programmes. Every resource is created to help real students understand their subjects, not just pass an exam.

Prepared by: Unnati Education Academic Content Team Subject Specialisation: Chemistry, including Chemical Energetics and Organic Chemistry Programme Reference: IGNOU BSCG, BSCBCH Examination Reference: IGNOU Term-End Examination December 2025

Explore More IGNOU BCHCT–133 Solved Papers and Study Material

Looking for more resources? Unnati Education offers solved question papers from previous IGNOU sessions, assignment solutions, and topic-wise study notes for BCHCT-133 and related chemistry courses. You can also find solved papers for other BSCG and BSCBCH courses on the platform. Browse through the available material and build a complete preparation kit for your IGNOU chemistry exams.

Get Your BCHCT 133 Question Paper December 2025 Solved Paper Now

You have seen the full paper. You know what the exam asks. Now is the time to get the answers. The BCHCT-133 December 2025 solved paper from Unnati Education gives you everything you need to prepare with confidence. Contact the team today, mention BCHCT-133 December 2025, and get your solved copy quickly. Do not leave your preparation to chance when a verified solved paper is available right now.