BCHCT 137 Guess Paper at a Glance
- Course code: BCHCT 137 (4 credits, theory)
- Course title: Coordination Chemistry, States of Matter and Chemical Kinetics
- Programmes: Bachelor of Science (General) (BSCG) and Bachelor of Science (Multidisciplinary) (BSCM)
- Questions in the file: 14 solved
- Shown on this page: 5 full sample answers
- Remaining in the paid file: 9 questions
- Blocks covered: 4 of 4 (all 14 units)
- Papers analysed: 5 sessions, June 2023 to December 2025
- Exam pattern: 2 hours, 50 marks, Part A 25 plus Part B 25
- Target sessions: June 2026 and December 2026
- Delivery: PDF on WhatsApp, 9899436384
The BCHCT 137 Solved Guess Paper 2026 is a 14-question predicted paper for IGNOU's Coordination Chemistry, States of Matter and Chemical Kinetics course, with a complete written answer under every question. It was built by reading five consecutive term-end papers line by line and marking which topics returned and which had gone quiet long enough to be due.
Each answer was then written the way a term-end evaluator expects to read it. This is not a topic list. Every one of the 14 questions arrives with its answer already written out in full.
If you have opened the BCHCT 137 book once and closed it again, you already know the problem. Two volumes, four blocks, fourteen units, and a paper that asks you for only ten answers of five marks each. The whole difficulty is knowing which ten. That is the gap this file was made to close.
What the BCHCT 137 Solved Guess Paper 2026 Actually Contains
The file holds 14 exam-style questions and 14 complete answers, spread across all four blocks of BCHCT 137 and both parts of the term-end paper. Each question is set at the five-mark weight IGNOU actually uses, and each answer runs to roughly the length you would write in the hall, not a two-line summary and not a three-page essay.
Above each answer sits a small header strip. It tells you the block and part the question belongs to, the sessions in which that topic last appeared, and a priority tag. So when you reach Q7 on Jahn-Teller distortion, you can already see that it surfaced in June 2025, December 2024 and June 2023 before you read a single line of the answer. That context is the difference between revising and guessing.
Seven of the 14 questions sit in Part A, covering d and f block elements and coordination chemistry. Seven sit in Part B, covering states of matter and chemical kinetics. That split is deliberate, because the paper demands five answers from each part and a lopsided guess paper would leave you stranded on one side of the answer book.
Answers are written strictly from the IGNOU textbook. Where the book uses a specific example, the answer uses that same example. Where the book gives a numbered set of postulates, the answer gives that same set in the same order. This is a study aid prepared by Unnati Educations and is not an official IGNOU publication. If you want to compare it against the source, the full BCHCT 137 self-learning material is hosted on eGyanKosh.
Five Sample Questions with Answers from the BCHCT 137 Guess Paper
The five answers below are reproduced word for word from the paid file, one from each block plus an extra from Block 2, so you can judge the writing before you pay anything. They are samples 1 to 5 here; inside the PDF they carry their original numbers Q1, Q4, Q6, Q10 and Q13. Read one all the way through. If the explanation lands, the other nine will land the same way.
Lanthanoid Contraction and Its Consequences
Exam question: Explain the term 'lanthanoid contraction' and discuss its important consequences.
Lanthanoid contraction is the gradual decrease in the atomic and ionic radii of the lanthanoids from cerium (Ce) to lutetium (Lu). It occurs because the 4f electrons provide poor shielding against the increasing nuclear charge. As a result, the effective nuclear charge increases across the series, pulling the outer electrons closer to the nucleus and causing a steady decrease in size.
Important consequences
- Similarity between 4d and 5d transition elements. The atomic radii of corresponding 4d and 5d transition elements become almost identical, so pairs such as Zr and Hf, Nb and Ta, Mo and W show very similar chemical properties.
- Difficulty in separation of 4d and 5d elements. Because these corresponding elements have nearly the same size and similar chemical behaviour, separating them from each other becomes difficult.
- Similarity among lanthanoids. The decrease in the size of Ln3+ ions is very small across the series, so all lanthanoids show closely similar chemical properties, which again makes separation difficult.
- Closer resemblance of 5d to 4d elements. The 5d transition elements resemble the 4d elements much more closely than the 3d elements, because lanthanoid contraction compensates for the expected increase in atomic size.
- Increase in charge density. The decrease in ionic size raises the charge density, which influences physical and chemical properties such as complex formation and bonding characteristics.
VBT, Inner and Outer Orbital Complexes
Exam question: Using Valence Bond Theory, explain why [Co(NH3)6]3+ and [CoF6]3- differ in their magnetic behaviour. Distinguish between inner and outer orbital complexes.
Both complexes contain Co3+, whose electronic configuration is 3d6. Their magnetic behaviour differs because NH3 is a strong-field ligand whereas F- is a weak-field ligand.
[Co(NH3)6]3+. NH3 causes pairing of electrons in the 3d orbitals. Two vacant 3d orbitals become available for hybridisation. The hybridisation is d2sp3, making it an inner orbital complex. All electrons are paired, so the complex is diamagnetic.
[CoF6]3-. F- is a weak-field ligand and does not pair the 3d electrons. Hybridisation involves 4s, 4p and two 4d orbitals, giving sp3d2, an outer orbital complex. Four unpaired electrons remain, so the complex is paramagnetic.
| Inner orbital complexes | Outer orbital complexes |
|---|---|
| Formed by strong-field ligands. | Formed by weak-field ligands. |
| Electrons pair in the (n-1)d orbitals. | No pairing occurs in the (n-1)d orbitals. |
| Hybridisation is d2sp3 (octahedral). | Hybridisation is sp3d2 (octahedral). |
| Uses inner d-orbitals for bonding. | Uses outer d-orbitals for bonding. |
| Usually diamagnetic or with fewer unpaired electrons. | Usually paramagnetic with more unpaired electrons. |
So [Co(NH3)6]3+ is an inner orbital, diamagnetic complex because NH3 causes electron pairing, whereas [CoF6]3- is an outer orbital, paramagnetic complex because F- does not.
Isomerism in Coordination Compounds
Exam question: Describe the different types of isomerism shown by coordination compounds, giving one example of each main class.
Coordination compounds show two main families of isomerism: structural isomerism and stereoisomerism.
Structural isomerism
Same molecular formula, different arrangement of atoms or ions.
- Ionisation isomerism arises when a ligand inside the coordination sphere swaps with an ion outside it. Example: [Co(NH3)5Br]SO4 and [Co(NH3)5SO4]Br.
- Hydrate or solvate isomerism arises from different positions of water molecules inside and outside the coordination sphere. Example: [Cr(H2O)6]Cl3 and [Cr(H2O)5Cl]Cl2.H2O.
- Linkage isomerism occurs when an ambidentate ligand coordinates through different donor atoms. Example: [Co(NH3)5(NO2)]Cl2 and [Co(NH3)5(ONO)]Cl2.
- Coordination isomerism arises from exchange of ligands between cationic and anionic complex ions. Example: [Co(NH3)6][Cr(CN)6] and [Cr(NH3)6][Co(CN)6].
Stereoisomerism
Same composition, different spatial arrangement of ligands.
- Geometrical isomerism: ligands occupy different positions around the central metal ion, cis or trans and fac or mer. Example: cis-[Pt(NH3)2Cl2] and trans-[Pt(NH3)2Cl2].
- Optical isomerism: isomers are non-superimposable mirror images that rotate plane-polarised light in opposite directions. Example: [Co(en)3]3+.
Surface Tension, Definition and Temperature Effect
Exam question: Define surface tension and give its unit. What is the effect of temperature on the surface tension of a liquid?
Surface tension is the force acting per unit length along the surface of a liquid, perpendicular to an imaginary line drawn on the surface. It may also be defined as the energy required to increase the surface area of a liquid by unit area.
Unit. The SI unit is N m-1, newton per metre. It may also be expressed as J m-2, joule per square metre.
Effect of temperature. Surface tension decreases as temperature increases. At higher temperatures the kinetic energy of the liquid molecules rises, which reduces the intermolecular cohesive forces at the surface. As those forces weaken, surface molecules feel less inward pull, so surface tension falls.
The decrease is nearly linear over a moderate temperature range. At the critical temperature the distinction between liquid and vapour disappears and the surface tension becomes zero.
Zero-Order Reaction, Rate Law and Plot
Exam question: What is a zero-order reaction? Derive its integrated rate law and draw the nature of its concentration-time plot.
A zero-order reaction is a reaction whose rate is independent of the concentration of the reactant. The rate law is Rate = k, where k is the zero-order rate constant.
Integrated rate law. For a reactant A, -d[A]/dt = k. On integration this gives [A] = [A]0 - kt, where [A]0 is the initial concentration, [A] is the concentration at time t, k is the zero-order rate constant and t is time.
Concentration-time plot. A plot of concentration [A] against time t is a straight line. The slope of the line is -k and the y-intercept is [A]0. The PDF carries the labelled graph beside this answer, which is the part most students lose the half mark on.
Those are 5 of the 14. The remaining 9 solved questions, including Actinoids versus Lanthanoids, CFSE, Jahn-Teller distortion, kinetic theory postulates, viscosity, Schottky and Frenkel defects, factors affecting reaction rate and activated complex theory, are in the paid file.
Message 9899436384 on WhatsAppHow the BCHCT 137 Guess Paper Was Built from Five Previous Year Papers
Five term-end papers were read in full and tallied topic by topic: June 2023, December 2023, December 2024, June 2025 and December 2025. The December 2025 paper, the most recent one available, was analysed last and given extra weight, because it tells you what the current paper setter is thinking.
The method is not complicated, but it is slow. Each question in each paper was tagged to a unit. Then the tags were counted. Anything appearing four or more times became a HIGH priority. Anything appearing two or three times became MEDIUM. Single appearances were logged as LOW and kept only as backup. A second rule was layered on top: a topic that used to repeat and has now been absent for two sessions gets pushed back up, because IGNOU rotates rather than retires.
That is how Factors Affecting the Rate of a Reaction ended up in the file at HIGH despite appearing only twice in the window. It ran in December 2024 and June 2023, then went quiet. Topics that behave like that tend to come back. The same logic applies to Activated Complex Theory, which last surfaced in December 2023.
Only after the tally was settled did anyone start writing. Each answer was drafted from the IGNOU textbook, checked against the phrasing the actual paper uses, then trimmed to something a student can reproduce in about twelve minutes. If you want to run the same exercise yourself, our IGNOU Previous Year Question Paper collection has the source papers, and the official December 2023 and June 2025 papers sit on the IGNOU question paper archive if you prefer to check them at source.
BCHCT 137 Topic Frequency Table, June 2023 to December 2025
Across five sessions, seven topics appeared in every single paper: colour of transition metal ions, VBT inner and outer orbital complexes, IUPAC names and formulae, CFSE, crystal systems and defects, and order of reaction and rate law. Those are the ones you cannot afford to leave out. The table below is an extract from page 14 of the file.
| Topic | Jun 2023 | Dec 2023 | Dec 2024 | Jun 2025 | Dec 2025 | Priority |
|---|---|---|---|---|---|---|
| Lanthanoid contraction and consequences | Yes | Yes | Yes | No | Yes | HIGH |
| Separation of lanthanoids | No | No | Yes | Yes | No | MEDIUM |
| Actinoids versus lanthanoids comparison | Yes | Yes | Yes | No | No | HIGH |
| Colour of transition metal ions and d-d transitions | Yes | Yes | Yes | Yes | Yes | HIGH |
| Electronic configuration and oxidation states | No | No | Yes | Yes | Yes | MEDIUM |
| Magnetic moment and unpaired electrons | No | Yes | Yes | Yes | Yes | MEDIUM |
| VBT, inner and outer orbital complexes | Yes | Yes | Yes | Yes | Yes | HIGH |
| IUPAC names and formulae of complexes | Yes | Yes | Yes | Yes | Yes | MEDIUM |
| Isomerism in coordination compounds | Yes | Yes | No | Yes | Yes | HIGH |
| Ligand types, mono, bi, ambidentate, poly | Yes | Yes | No | No | No | LOW |
| CFSE in octahedral weak and strong fields | Yes | Yes | Yes | Yes | Yes | HIGH |
| Jahn-Teller and tetragonal distortion | Yes | No | Yes | Yes | No | HIGH |
| Role of metals in biological systems | No | Yes | Yes | Yes | No | MEDIUM |
| Spectrochemical series and splitting diagrams | No | No | No | Yes | Yes | LOW |
| Postulates of the kinetic theory of gases | No | No | Yes | Yes | No | HIGH |
| Ideal gas and van der Waals equation | No | Yes | No | Yes | Yes | MEDIUM |
| Maxwell-Boltzmann distribution | No | No | Yes | Yes | No | MEDIUM |
| Surface tension, definition and temperature effect | No | No | Yes | Yes | Yes | HIGH |
| Viscosity versus temperature in liquids and gases | Yes | Yes | Yes | Yes | No | HIGH |
| Crystal systems, unit cell and defects | Yes | Yes | Yes | Yes | Yes | HIGH |
| Order of reaction and rate law | Yes | Yes | Yes | Yes | Yes | HIGH |
| Factors affecting rate of reaction | Yes | No | Yes | No | No | HIGH |
| Zero-order reaction and integrated law | No | Yes | No | No | Yes | HIGH |
| Activated complex and collision theory | Yes | Yes | No | No | No | HIGH |
Notice how uneven the middle rows are. Spectrochemical series only started showing up in June 2025 and December 2025, which is why it sits at LOW despite being recent. Two appearances at the tail of the window is a trend, not yet a pattern. That distinction is the whole job of a guess paper.
Block and Unit Index of BCHCT 137 with Examinable Topics
BCHCT 137 is a 4-credit theory course split into two volumes, four blocks and 14 units, with Part A worth two credits and Part B worth two credits. The table below gives every unit with the specific topics that have actually been examined from it, not a restatement of the unit title.
| Block and unit | Unit title | Topics that carry exam weight |
|---|---|---|
| Block 1, Unit 1 | Transition Elements I | Periodic trends in atomic radii and density, ionisation energy, stability of oxidation states for Mn, Fe and Cu, Latimer diagrams |
| Block 1, Unit 2 | Transition Elements II | Formation of complexes, colour of transition metal compounds, magnetic properties, catalytic behaviour |
| Block 1, Unit 3 | Inner-Transition Elements | Lanthanide contraction, oxidation states, colour of ions, separation of lanthanides by ion exchange |
| Block 2, Unit 4 | Coordination Chemistry I | Werner's coordination theory, ligands and coordination number, IUPAC nomenclature of complexes |
| Block 2, Unit 5 | Coordination Chemistry II | Structural and stereoisomerism for coordination numbers 4 and 6, valence bond theory, inner and outer orbital complexes of Cr, Fe, Co, Ni and Cu |
| Block 2, Unit 6 | Crystal Field Theory I | Octahedral splitting, CFSE, weak and strong field effects, factors affecting splitting magnitude, spectrochemical series |
| Block 2, Unit 7 | Crystal Field Theory II | Tetrahedral and square planar splitting, CFSE comparison for Oh and Td, tetragonal distortion, Jahn-Teller effect |
| Block 3, Unit 8 | Kinetic Theory of Gases | Postulates of the kinetic theory, kinetic gas equation, Maxwell-Boltzmann distribution, equipartition of energy, mean free path |
| Block 3, Unit 9 | Real Gases and their Liquefaction | Compressibility factor and causes of deviation, van der Waals equation, Boyle temperature, Andrews isotherms of CO2, critical constants |
| Block 3, Unit 10 | Liquids | Structure of liquids, surface tension and its determination, coefficient of viscosity, temperature effect on both |
| Block 3, Unit 11 | Solids I | Amorphous versus crystalline solids, symmetry elements, Bravais lattices and crystal systems, laws of crystallography, Miller indices |
| Block 3, Unit 12 | Solids II | X-ray diffraction and Bragg's law, structures of NaCl, KCl and CsCl, Schottky and Frenkel defects, glasses and liquid crystals |
| Block 4, Unit 13 | Chemical Kinetics I | Factors affecting reaction rate, rate law and rate constant, order versus molecularity, integrated rate laws for zero, first and second order |
| Block 4, Unit 14 | Chemical Kinetics II | Initial rate, integral, graphical, half-life and isolation methods, collision theory, activated complex theory, Arrhenius comparison |
Read that third column once before you open the book. It tells you where the marks live. Units 5, 6, 7, 10, 12 and 13 between them account for the large majority of the questions in the five papers we tallied, which is exactly why 11 of the 14 questions in the guess paper are drawn from them. If you want the underlying reading for any unit, the BCHCT 137 Study Material page collects the block PDFs and notes in one place.
BCHCL 138 Practical File and How It Sits Beside BCHCT 137
BCHCT 137 is the 4-credit theory course; the practical component is a separate 2-credit course, BCHCL 138, and the two must be taken together. This guess paper covers the theory paper only. It will not help you in the lab viva, and it does not pretend to.
Plenty of students discover this in April, panicking. The lab course carries its own record file, its own experiments and its own practical examination held at your allotted study centre, and it is assessed independently of the term-end theory paper. A good theory score cannot rescue a missing practical file.
Unnati Educations prepares the BCHCL 138 practical file separately, written in the standard aim, apparatus, theory, procedure, observation, calculation and result format that examiners expect. Because the experiment list is issued centre-wise and can vary, we confirm your exact experiment list against your study centre before preparing anything. Send your enrolment number and study centre code to 9899436384 on WhatsApp and we will confirm what your file needs to contain.
BCHCT 137 Exam Pattern, Marking Scheme and Answer Rules
The BCHCT 137 term-end paper runs for 2 hours and carries 50 marks, split into Part A worth 25 marks and Part B worth 25 marks, and you attempt any five questions from each part with every question carrying 5 marks. The two parts are answered in two separate answer books, each labelled with your enrolment number, course code and part title.
That structure has a consequence most students miss. Ten answers in 120 minutes leaves you roughly eleven minutes per answer including reading and selection time. An answer that runs to two pages is not a better answer; it is a slower one. Every answer in the guess paper is written to that eleven-minute reality.
Three habits earn marks reliably in this paper. Open with a clean textbook definition and name the scholar or law where one exists, Jahn and Teller or Maxwell and Boltzmann for instance. Pair each theory with the specific example the IGNOU book uses, such as [Co(NH3)6]3+ against [CoF6]3-. And draw a comparison table wherever two things are being contrasted, because a table is faster to write and faster to mark.
Equally, some things are not worth your evenings. Long numerical-only items such as CFSE value sums, Miller indices and density calculations reward method practice but rarely carry safe marks. Rare single-appearance topics such as liquid crystals and the law of corresponding states can wait. Full IUPAC naming lists are better learned as rules than memorised as dozens of formulae.
Who the BCHCT 137 Solved Guess Paper Is Meant For
This file is built for BSCG and BSCM students sitting BCHCT 137 in June 2026 or December 2026, particularly those with four weeks or less of preparation time left. It is not a replacement for the textbook and it does not claim to be.
It suits you if you are working or studying alongside a job and cannot get through two volumes; if you have already failed BCHCT 137 once and want to know precisely where to aim this time; if you have finished the assignment but never sat with a past paper; or if you simply want a written model answer to compare your own attempt against. Distance learners revising alone benefit most, because the file substitutes for the sense of priority a classroom would normally give you.
It suits you less if you are aiming for a distinction in chemistry, or if you plan to continue into BCHET 147 and the later electives. In that case use the guess paper as a revision spine and read the units properly around it. Students taking other Chemistry, Physics or Zoology core papers in the same session often pick up the matching BSCG Guess Paper for each code and revise them as a set.
How to Get the Complete BCHCT 137 Guess Paper on WhatsApp
Message 9899436384 on WhatsApp with your course code and session, and we will confirm availability, price and delivery time before you pay anything. There is no login, no cart and no account to create.
Say which session you are appearing in, June 2026 or December 2026, and whether you need the theory guess paper alone or the BCHCL 138 practical file alongside it. The complete 14-page PDF is sent to the same WhatsApp number once your enquiry is confirmed. Five of the 14 answers are already on this page in full, so you know exactly what the other 9 will read like.
If you are taking more than one paper this session, ask on the same chat rather than opening a new one. Our full IGNOU Solved Guess Paper catalogue covers the other core codes for the same sessions, and bundling saves you the back and forth.
BCHCT 137 Guess Paper: Frequently Asked Questions
The nine questions below are the ones students actually message us about before buying: session validity, how many answers are held back, whether Part B is covered, and how BCHCL 138 fits in.
Is the BCHCT 137 Solved Guess Paper valid for both the June 2026 and December 2026 sessions?
Yes. One PDF covers both sittings. IGNOU runs BCHCT 137 only in June and December, and the syllabus does not change between them. Topic priorities were set from five papers ending with December 2025, so the analysis holds for the whole of 2026. If IGNOU revises the course before December 2026, we reissue the file at no extra charge.
How many questions does the BCHCT 137 guess paper contain and how many are shown here?
The complete file contains 14 solved questions across 14 pages. Five full answers are published on this page as samples, which leaves 9 questions in the paid file. Those 9 include actinoids versus lanthanoids, colour of transition metal ions, CFSE, Jahn-Teller distortion, kinetic theory postulates, viscosity and temperature, Schottky and Frenkel defects, factors affecting reaction rate, and activated complex theory.
Does the BCHCT 137 guess paper cover both Part A and Part B of the paper?
Yes, and the split is even. Seven questions cover Part A, which is d and f block elements and coordination chemistry from Blocks 1 and 2. Seven cover Part B, which is states of matter and chemical kinetics from Blocks 3 and 4. Since the term-end paper requires five answers from each part in separate answer books, a guess paper weighted towards one part would be useless. All 14 units are represented.
Are the BCHCT 137 answers written from the official IGNOU textbook?
Every answer is written from the IGNOU BCHCT 137 self-learning material, using the book's own definitions, examples and numbered lists. Where the textbook contrasts [Co(NH3)6]3+ with [CoF6]3-, the answer uses that same pair. This is a study aid prepared by Unnati Educations and is not an official IGNOU publication, and the original blocks remain freely available on eGyanKosh.
Can the BCHCT 137 guess paper guarantee that these exact questions will appear?
No, and nobody honestly can. A guess paper is a probability exercise, not a leak. What it does is concentrate your revision on topics that have repeated across five consecutive sessions, which is a far better use of limited time than reading 14 units at random. Seven of the topics in the file appeared in all five papers analysed. Treat the file as a priority map and read the textbook around it.
Is the BCHCT 137 guess paper useful for the assignment or only for the term-end exam?
It is built for the term-end examination. The BCHCT 137 tutor-marked assignment is a separate 100-mark submission with its own question set, released fresh each session, and it carries 30 per cent continuous evaluation weightage. The guess paper answers do overlap in topic, so they help you understand the concepts, but they are not assignment answers. The solved assignment is a separate product.
Does the BCHCT 137 file include the BCHCL 138 practical file as well?
No. BCHCT 137 is the 4-credit theory course and BCHCL 138 is the 2-credit laboratory course taken alongside it. They are examined separately and the guess paper covers the theory paper only. We do prepare BCHCL 138 practical files, but as a separate product and only after confirming your experiment list against your study centre. Ask for both on the same WhatsApp chat if you need them together.
How is the BCHCT 137 guess paper delivered after I enquire?
As a PDF on WhatsApp, sent to the number you message from. Send your course code and session to 9899436384, and price, availability and delivery time are confirmed on chat before any payment. The file is 14 pages, readable on a phone and clean enough to print for the last week of revision. There is no account to create and no download portal to log into.
Which programmes and semester does BCHCT 137 belong to?
BCHCT 137 is a Discipline Specific Core course in Chemistry, worth 4 credits, offered under Bachelor of Science (General) (BSCG) and Bachelor of Science (Multidisciplinary) (BSCM). It is normally taken in the fourth semester alongside its laboratory course BCHCL 138. Students choosing Chemistry as one of their three disciplines will sit this paper as part of the core requirement rather than as an elective.