BCS Written Chemistry study guide
BCS Written Chemistry · Work through your exam, one topic at a time.
The BCS Written Chemistry examination is the descriptive, essay-type stage of the Bangladesh Civil Service (BCS) recruitment process for candidates who have already cleared the preliminary screening and are competing for cadre posts that require a chemistry background. It is intended for graduates in chemistry or closely related fields who can explain principles in continuous prose, not merely select options. The BCS Written Chemistry study guide has 8 sections and about 2,457 words.
01Atomic Structure and Periodicity: What BCS Candidates Must Master
Begin with the quantum-mechanical picture: principal, azimuthal, magnetic and spin quantum numbers, the rules governing them (n ≥ 1, l = 0 to n−1, m = −l to +l, m s = ±½), and the building-up sequence that produces electron configurations. Know the Aufbau principle, Hund's rule and the Pauli exclusion principle as separate statements, because questions often test which rule a given configuration violates.
336 words, about 2 min02Chemical Bonding and Molecular Structure: From Lewis to VSEPR and MO
Candidates must move comfortably between four models. Lewis structures give connectivity and formal charge; check that the sum of formal charges equals the overall charge.
330 words, about 2 min03Physical Chemistry: Thermodynamics, Kinetics and Electrochemistry
Thermodynamics: distinguish state functions (U, H, S, G) from path functions (q, w). Apply the first law, ΔU = q + w, and know the sign convention used.
317 words, about 2 min04Organic Chemistry: Reactions, Mechanisms and Synthesis
Build your answers around mechanism, not memorised equations. For substitution , distinguish SN1 (carbocation intermediate, racemisation, favoured by tertiary substrates and polar protic solvents) from SN2 (concerted backside attack, inversion, favoured by methyl/primary substrates and polar aprotic solvents).
257 words, about 1 min05Inorganic Chemistry: Coordination and Transition Metal Chemistry
Master the vocabulary of coordination compounds: central metal, ligand, coordination number, oxidation state, and the difference between monodentate and polydentate ligands (EDTA is hexadentate). Apply IUPAC naming rules: ligands alphabetically, anionic ligands ending in -o, then the metal with its oxidation state in Roman numerals.
324 words, about 2 min06Analytical and Instrumental Chemistry: Choosing and Interpreting a Method
Candidates should be able to select a technique for a stated analyte and interpret its output. Titrimetry: acid–base, redox (permanganometry, iodometry), complexometric (EDTA) and precipitation methods; know primary standards (oxalic acid, potassium dichromate, sodium carbonate) and indicators (phenolphthalein, methyl orange, starch, Eriochrome Black T).
300 words, about 2 min07Environmental and Industrial Chemistry: Pollution, Processes and Control
Environmental chemistry: understand the composition of the atmosphere, the greenhouse effect (CO₂, CH₄, N₂O, CFCs), ozone depletion by chlorine radicals, acid rain from SO₂ and NOₓ, photochemical smog from NOₓ and hydrocarbons, and water-quality parameters (BOD, COD, DO, pH, hardness). Know primary versus secondary pollutants and the difference between point and non-point sources.
307 words, about 2 min08Chemistry of Bangladesh: Agriculture, Industry and Public Health
This domain applies the other seven to Bangladesh's own context. Agriculture: know the role of urea, TSP, MoP and DAP as N, P, K and combined fertilisers; understand soil pH and why liming corrects acidity; recognise the importance of the Sundarbans and salinity in coastal agriculture; and be aware of pesticide residues and integrated pest management.
286 words, about 1 min