Chemistry
रसायन विज्ञान · Class 11 · Code 3011 (CDC Che.301)
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chapters done
- General and Physical Chemistry
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The syllabus asks for
- General introduction of chemistry
- Importance and scope of chemistry
- Basic concepts: atoms, molecules, relative masses of atoms and molecules, amu, radicals, molecular formula, empirical formula
- Percentage composition from molecular formula
Key points
- Chemistry studies the composition, structure, properties and transformations of matter; its main branches are physical, inorganic, organic, analytical, biochemistry, industrial, nuclear and environmental.
- An atom is the smallest particle of an element taking part in a reaction; a molecule is the smallest particle able to exist independently.
- 1 atomic mass unit = 1/12 of the mass of one ¹²C atom = 1.66054 × 10⁻²⁴ g.
- Relative atomic and molecular masses are ratios and carry no unit; molecular mass is the sum of the atomic masses in the formula.
- A radical is a charged atom or group of atoms that acts as one unit; formulae are built by criss-crossing valencies.
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The syllabus asks for
- Dalton's atomic theory and its postulates
- Laws of stoichiometry
- Avogadro's law and deductions: molecular mass and vapour density; molecular mass and volume of gas; molecular mass and number of particles
- Mole and its relation with mass, volume and number of particles
- Calculations based on mole concept
- Limiting reactant and excess reactant
- Theoretical yield, experimental yield and percentage yield
- Calculation of empirical and molecular formula from percentage composition
Key points
- Dalton's postulates: atoms are indivisible, conserved, identical within an element and combine in small whole-number ratios. Isotopes and subatomic particles have since disproved the first and third.
- The mass laws: conservation of mass, definite proportions, multiple proportions, reciprocal proportions, and Gay-Lussac's law of gaseous volumes.
- Avogadro's law: equal volumes of gases at the same T and P contain equal numbers of molecules. Deductions: molecular mass = 2 × vapour density; 1 mol of gas occupies 22.4 L at STP; 1 mol contains NA = 6.022×10^23 particles.
- Mole conversions: n = w/M = N/NA = V/22.4 (V in litres, at STP).
- Stoichiometry route: mass → moles → mole ratio from the balanced equation → moles → mass or volume.
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The syllabus asks for
- Rutherford's atomic model and its limitations
- Postulates of Bohr's atomic model and its application
- Spectrum of hydrogen atom
- Defects of Bohr's theory
- Elementary idea of quantum mechanical model: de Broglie's wave equation
- Heisenberg's Uncertainty Principle
- Concept of probability
- Quantum Numbers
- Orbitals and shape of s and p orbitals only
- Aufbau Principle; Pauli's exclusion principle; Hund's rule
- Electronic configurations of atoms and ions (up to atomic number 30)
Key points
- Rutherford's α-scattering proved the nuclear atom but predicted an unstable atom and a continuous spectrum, and said nothing about electron arrangement.
- Bohr quantised angular momentum, mvr = nh/2π, giving rn = 0.529 n^2/Z Å and En = -13.6 Z^2/n^2 eV, and radiation only on transitions, Δ E = hν.
- Hydrogen line spectrum: 1/λ = RH(1/n1^2 - 1/n2^2) with RH = 1.097×10^7 m^-1; Lyman (UV, n1=1), Balmer (visible, n1=2), Paschen, Brackett, Pfund (IR).
- Bohr fails for many-electron atoms, fine structure, Zeeman and Stark effects, and contradicts both wave–particle duality and the uncertainty principle.
- De Broglie: λ = h/mv. A Bohr orbit is a standing wave, 2π r = nλ.
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The syllabus asks for
- Modern periodic law and modern periodic table; classification into groups, periods and blocks
- IUPAC classification of elements
- Nuclear charge and effective nuclear charge
- Periodic trend and periodicity: atomic radii, ionic radii, ionization energy, electron affinity, electronegativity, metallic character
Key points
- Modern periodic law: properties are periodic functions of atomic number, established by Moseley's relation √ν = a(Z-b).
- The long form has 7 periods (2, 8, 8, 18, 18, 32, 32 elements) and 18 IUPAC groups; blocks s, p, d, f are named after the subshell filled last.
- Elements with Z > 100 are named systematically from the roots nil, un, bi, tri, quad, pent, hex, sept, oct, enn plus -ium.
- Zeff = Z - σ; screening power falls as s > p > d > f. Slater's rules give Zeff = 2.20 for Na(3s) and 6.10 for Cl(3p).
- Across a period: radius ↓, IE ↑, EA ↑, EN ↑, metallic character ↓. Down a group: radius ↑, IE ↓, EA ↓, EN ↓, metallic character ↑.
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The syllabus asks for
- Valence shell, valence electron and octet theory
- Ionic bond and its properties
- Covalent bond and coordinate covalent bond; properties of covalent compounds
- Lewis dot structure of common compounds of s and p block elements
- Resonance
- VSEPR theory and shapes of simple molecules (BeF2, BF3, CH4, CH3Cl, PCl5, SF6, H2O, NH3, CO2, H2S, PH3)
- Elementary idea of Valence Bond Theory
- Hybridization involving s and p orbitals only
- Bond characteristics: bond length, ionic character, dipole moment
- Van der Waals' force and molecular solids
- Hydrogen bonding and its application
- Metallic bonding and properties of metallic solids
Key points
- Atoms bond to reach a noble-gas octet (duplet for H). The octet rule fails for incomplete octets (BF₃), expanded octets (SF₆), odd-electron molecules (NO) and noble-gas compounds.
- Ionic bond = complete transfer (ΔEN > 1.7), giving a non-directional giant lattice: high melting point, conducts only when molten or aqueous.
- Covalent bond = shared pairs; a coordinate bond is a shared pair donated entirely by one atom (NH₄⁺, H₃N→BF₃).
- Lewis structures: shared pairs S = N - A; lone pairs = (A-S)/2; formal charge = valence − lone-pair electrons − ½(bonding electrons).
- Resonance: one hybrid structure, not a mixture; it equalises bond lengths and lowers the energy by the resonance energy.
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The syllabus asks for
- General and electronic concept of oxidation and reduction
- Oxidation number and rules for assigning oxidation number
- Balancing redox reactions by oxidation number and ion-electron (half reaction) method
- Electrolysis: qualitative aspect; quantitative aspect (Faraday's laws of electrolysis)
Key points
- Classically, oxidation is addition of oxygen or removal of hydrogen; electronically it is loss of electrons (OIL RIG). Reduction is the reverse, and the two always occur together.
- The oxidising agent gains electrons and is reduced; the reducing agent loses electrons and is oxidised. In disproportionation one element does both.
- Oxidation number is the charge an atom would have if all bonds were ionic. Key rules: free element 0; H = +1 (−1 in hydrides); O = −2 (−1 in peroxides); the sum equals 0 for a molecule and the charge for an ion.
- Oxidation number can be fractional (Fe₃O₄ = +8/3, Na₂S₄O₆ = +2.5) because it is an average; valency never can.
- Oxidation number method: equalise total increase with total decrease, then balance the rest by inspection.
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The syllabus asks for
- Gaseous state: Kinetic theory of gas and postulates
- Gas laws: Boyle's and Charles' law; Avogadro's law; Combined gas equation; Dalton's law of partial pressure; Graham's law of diffusion
- Ideal gas and ideal gas equation; Universal gas constant and its significance
- Deviation of real gas from ideality
- Liquid state: evaporation and condensation; vapour pressure and boiling point; surface tension and viscosity (qualitative)
- Liquid crystals and their applications
- Solid state: types of solids; amorphous and crystalline solids
- Efflorescent, deliquescent and hygroscopic solids
- Crystallization and crystal growth; water of crystallization
- Introduction to unit crystal lattice and unit cell
Key points
- Kinetic gas equation: PV = (1)/(3)mNc^2, giving crms = √3RT/M = √3P/ρ and kinetic energy per mole E = (3)/(2)RT.
- Gas laws: Boyle P1V1 = P2V2; Charles V1/T1 = V2/T2; combined P1V1/T1 = P2V2/T2; Dalton P = Σ pi with pi = xiP; Graham r1/r2 = √M2/M1.
- Ideal gas equation PV = nRT = (w/M)RT, so M = ρ RT/P; R = 8.314 J K^-1mol^-1 = 0.0821 L atm K^-1mol^-1, the work done by one mole per kelvin at constant pressure.
- Real gases deviate because molecules attract and occupy volume: Z = PV/nRT ≠ 1, and left(P + an^2/V^2right)(V-nb) = nRT.
- Vapour pressure rises with temperature; a liquid boils when its vapour pressure equals the external pressure. Surface tension (γ, N m⁻¹) and viscosity (η, Pa s) both fall as temperature rises.
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The syllabus asks for
- Physical and chemical equilibrium
- Dynamic nature of chemical equilibrium
- Law of mass action
- Expression for equilibrium constant and its importance
- Relationship between Kp and Kc
- Le Chatelier's Principle (numericals not required)
Key points
- Chemical equilibrium is the state of a reversible reaction in a closed system where the forward and backward rates are equal. It is dynamic, reachable from either side, and unaffected in position by a catalyst.
- Law of mass action: rate ∝ product of active masses (molar concentrations), each raised to its stoichiometric coefficient.
- For aA + bB ⇌ cC + dD, Kc = dfrac[C]^c[D]^d[A]^a[B]^b and Kp = dfracpC^cpD^dpA^apB^b; pure solids and pure liquids are omitted.
- Kp = Kc(RT)^Δ n with Δ n the change in gaseous moles; Kp = Kc when Δ n = 0.
- K measures the extent of reaction and depends only on temperature; comparing the reaction quotient Q with K predicts the direction of change.
- Inorganic Chemistry
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The syllabus asks for
- Hydrogen: atomic and nascent hydrogen; isotopes and uses; hydrogen as fuel; heavy water [with 9.2, 9.3 = 4 hrs]
- Allotropes of Oxygen: allotropy; types of oxides (acidic, basic, neutral, amphoteric, peroxide, mixed); applications of H2O2; medical and industrial application of oxygen
- Ozone: occurrence; preparation from oxygen; structure; test; ozone layer depletion; uses
- Nitrogen [5 hrs]: inertness and active nitrogen; chemical properties of ammonia and applications; harmful effects; oxy-acids of nitrogen (name and formula); chemical properties of nitric acid; ring test for nitrate ion
- Halogens [5 hrs]: general characteristics; comparative preparation, chemical properties and uses of Cl2, Br2, I2; tests; haloacids HCl, HBr, HI
- Carbon [with phosphorus = 3 hrs]: allotropes including fullerenes; properties and uses of carbon monoxide
- Phosphorus: allotropes (name only); phosphine
- Sulphur [5 hrs]: allotropes and uses; hydrogen sulphide including Kipp's apparatus; sulphur dioxide; sulphuric acid; sodium thiosulphate
Key points
- Hydrogen: nascent hydrogen is more reactive than H₂ because the 436 kJ mol⁻¹ H–H bond need not be broken. Isotopes protium, deuterium (D₂O, reactor moderator) and tritium. As a fuel: 143 kJ g⁻¹, only water, but hard to store.
- Oxides: acidic (CO₂, SO₂), basic (Na₂O, CaO), amphoteric (ZnO, Al₂O₃), neutral (CO, NO), peroxide (Na₂O₂, BaO₂), mixed (Fe₃O₄, Pb₃O₄). H₂O₂ strength in g L⁻¹ = volume strength × 3.04.
- Ozone: 3O₂ ⇌ 2O₃, ΔH = +284 kJ, made by silent electric discharge; angular, 116.8°, both O–O bonds 128 pm, a resonance hybrid; turns starch–iodide paper blue; destroyed catalytically by Cl radicals from CFCs.
- Nitrogen is inert because of the 941 kJ mol⁻¹ N≡N bond; active nitrogen is atomic and very reactive. Ammonia: 2NH₄Cl + Ca(OH)₂ → CaCl₂ + 2NH₃↑ + 2H₂O, dried over quicklime only, tested with HCl (white fumes) and Nessler's reagent (brown ppt).
- Nitric acid gives NO₂ (conc.) or NO (dil.) with metals, never H₂. Nitrate is confirmed by the brown ring [Fe(NO)]SO₄. Oxy-acids: H₂N₂O₂, HNO₂, HNO₃.
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The syllabus asks for
- Metals and Metallurgical Principles [5 hrs]: metallurgy types; ores; gangue, flux, slag, alloy, amalgam; general principles of extraction (concentration, calcination and roasting, smelting, carbon reduction, thermite and electrochemical reduction); refining (poling and electro-refinement)
- Alkali Metals [with alkaline earth = 5 hrs]: general characteristics; sodium via Down's process; NaOH; Na2CO3
- Alkaline Earth Metals: general characteristics; formulae and uses of quick lime, bleaching powder, magnesia, plaster of paris, epsom salt; solubility trends; stability of carbonates and nitrates
Key points
- A mineral becomes an ore only when extraction from it is profitable. Gangue is the earthy impurity, flux combines with gangue to give fusible slag, an alloy is a homogeneous mixture of metals and an amalgam is an alloy containing mercury.
- Concentration uses a physical difference: levigation (density), magnetic separation, froth flotation (sulphides), leaching (bauxite by Bayer's process, Ag by cyanide).
- Calcination (limited air) removes H₂O and CO₂ from carbonate and hydrated ores; roasting (excess air) converts sulphides to oxides, 2ZnS + 3O₂ → 2ZnO + 2SO₂↑.
- Reduction: carbon/CO for moderately reactive metals (blast furnace, Fe₂O₃ + 3CO → 2Fe + 3CO₂); self-reduction for Cu and Pb (2Cu₂O + Cu₂S → 6Cu + SO₂↑); aluminothermite for Cr and Mn (Cr₂O₃ + 2Al → 2Cr + Al₂O₃); electrolysis of the fused salt for Na, Mg, Al.
- Refining: liquation, distillation, poling (Cu₂O + CO → 2Cu + CO₂) and electro-refinement, in which the impure metal is the anode, the pure metal the cathode, and Ag/Au/Pt collect as anode mud.
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The syllabus asks for
- Introduction
- Micro and macro nutrients
- Importance of metal ions in biological systems (Na, K, Mg, Ca, Fe, Cu, Zn, Ni, Co, Cr)
- Ion pumps: sodium-potassium and sodium-glucose pump
- Metal toxicity: iron, arsenic, mercury, lead, cadmium
Key points
- Bio-inorganic chemistry studies the role of inorganic elements, especially metal ions, in living systems. About 25 elements are essential to humans; 11 of them make up 99.9% of body mass.
- Macronutrients are needed in more than about 100 mg per day and make up more than 0.01% of body mass (O, C, H, N, Ca, P, K, S, Na, Cl, Mg); micronutrients are needed in smaller amounts (Fe, Zn, Cu, Mn, I, F, Se, Cr, Co, Mo, Ni).
- Na⁺ is the main extracellular and K⁺ the main intracellular cation; Mg²⁺ is the centre of chlorophyll and the partner of ATP; Ca²⁺ builds bone as Ca₅(PO₄)₃OH and triggers clotting and muscle contraction.
- Fe²⁺ in the porphyrin ring of haem carries O₂ (Hb + 4O₂ ⇌ Hb(O₂)₄) and Fe in cytochromes transfers electrons; Cu works in cytochrome c oxidase and haemocyanin; Zn²⁺ is the Lewis acid of carbonic anhydrase; Ni²⁺ is in urease; Co³⁺ is in vitamin B₁₂; Cr³⁺ helps insulin act.
- The Na⁺/K⁺-ATPase is primary active transport: 3 Na⁺ out and 2 K⁺ in per ATP, which makes it electrogenic and maintains the −70 mV resting potential.
- Organic Chemistry
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The syllabus asks for
- Introduction to organic chemistry and organic compounds
- Reasons for separate study of organic compounds
- Tetra-covalency and catenation properties of carbon
- Classification of organic compounds
- Alkyl groups, functional groups and homologous series
- Structural formula, contracted formula and bond line structural formula
- Preliminary idea of cracking and reforming; quality of gasoline; octane number; cetane number; gasoline additive
Key points
- Organic chemistry is the chemistry of hydrocarbons and their derivatives. The vital force theory died when Wöhler made urea from ammonium cyanate in 1828, NH₄CNO --Δ--> NH₂CONH₂.
- Organic compounds are studied separately because of their number, their isomerism, their covalent character, their slow molecular reactions and their functional-group chemistry.
- Carbon is tetracovalent: promotion of a 2s electron gives four unpaired electrons, four sp³ hybrid orbitals and a tetrahedral angle of 109°28′. Catenation is possible because the C–C bond (348 kJ mol⁻¹) is far stronger than Si–Si, N–N or O–O.
- Compounds are classified as acyclic, or cyclic — homocyclic (alicyclic or aromatic, benzenoid or non-benzenoid) and heterocyclic.
- An alkyl group is CₙH₂ₙ₊₁; a functional group decides chemical behaviour; a homologous series has one general formula, a constant difference of –CH₂– (14 u), identical chemical properties and a regular gradation of physical properties.
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The syllabus asks for
- IUPAC Nomenclature of Organic Compounds (up to chain having 6 carbon atoms)
- Qualitative analysis: detection of N, S and halogens by Lassaigne's test
- Isomerism: definition and classification
- Structural isomerism: chain, position, functional, metamerism and tautomerism
- Geometrical isomerism (cis and trans) and optical isomerism (d and l form)
- Reaction Mechanism: homolytic and heterolytic fission
- Electrophiles, nucleophiles and free radicals
- Inductive effect (+I and -I); Resonance effect (+R and -R)
Key points
- An IUPAC name is secondary prefix + word root + primary suffix + secondary suffix. Choose the longest chain containing the senior functional group, number for the lowest locant to that group, list substituents alphabetically, and elide the final "e" before a vowel.
- Lassaigne's test fuses the compound with sodium to make NaCN, Na₂S and NaX. Nitrogen gives Prussian blue Fe₄[Fe(CN)₆]₃; sulphur gives a violet nitroprusside colour and a black PbS precipitate; halogens give AgCl (white), AgBr (pale yellow) or AgI (yellow) after the extract is boiled with dilute HNO₃.
- Isomers share a molecular formula. Structural isomerism = chain, position, functional, metamerism, tautomerism. Stereoisomerism = geometrical and optical.
- Geometrical isomerism needs restricted rotation and two different groups on each doubly bonded carbon. Trans is the more stable and higher-melting; cis is the more polar and higher-boiling.
- Optical isomerism needs a chiral carbon (four different groups). Enantiomers rotate polarised light equally and oppositely; a 50:50 racemic mixture and a meso form are both optically inactive; n chiral centres give up to 2^n isomers.
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The syllabus asks for
- Alkanes: preparation from haloalkanes (reduction and Wurtz reaction), decarboxylation, catalytic hydrogenation of alkene and alkyne
- Alkanes chemical properties: substitution (halogenation, nitration, sulphonation); oxidation of ethane
- Alkenes: preparation by dehydration of alcohol, dehydrohalogenation, catalytic hydrogenation of alkyne
- Alkenes chemical properties: addition with HX (Markovnikov's rule and peroxide effect), H2O, O3, H2SO4
- Alkynes: preparation from carbon and hydrogen, 1,2-dibromoethane, chloroform/iodoform
- Alkynes chemical properties: addition with H2, HX, H2O; acidic nature (sodium, ammoniacal AgNO3, ammoniacal Cu2Cl2)
- Test of unsaturation (ethene and ethyne): bromine water test and Baeyer's test
- Comparative physical properties of alkane, alkene and alkyne
- Kolbe's electrolysis method
Key points
- Alkanes are made by reducing haloalkanes (same carbon count), by the Wurtz reaction with Na in dry ether (double the carbons), by heating RCOONa with soda lime (one carbon fewer) and by hydrogenating alkenes or alkynes over Ni.
- Alkanes undergo free-radical substitution — halogenation (hν), vapour-phase nitration (673–773 K) and sulphonation with oleum — and are oxidised stepwise to alcohol, aldehyde, acid and finally CO₂ + H₂O.
- Alkenes are made by elimination: dehydration of alcohols (conc. H₂SO₄, 443 K), dehydrohalogenation with alcoholic KOH, and partial hydrogenation of an alkyne over Lindlar's catalyst. Saytzeff's rule gives the more substituted alkene.
- Alkenes undergo electrophilic addition. HX follows Markovnikov's rule because the more stable carbocation forms; HBr with peroxide goes the other way. Hydration gives alcohols; H₂SO₄ gives alkyl hydrogen sulphates; ozonolysis followed by Zn/H₂O cleaves the molecule at the double bond.
- Alkynes come from C + H₂ in an electric arc, from 1,2-dibromoethane with alcoholic KOH, from CHCl₃ or CHI₃ with silver, and industrially from CaC₂ + H₂O. They add H₂, HX and H₂O (giving CH₃CHO from ethyne, ketones from all others).
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The syllabus asks for
- Introduction and characteristics of aromatic compounds
- Huckel's rule of aromaticity
- Kekule structure of benzene
- Resonance and isomerism
- Preparation of benzene from decarboxylation of sodium benzoate, phenol, and ethyne
- Physical properties of benzene
- Chemical properties: addition (hydrogen, halogen); electrophilic substitution and orientation of benzene derivatives (o, m, p); nitration; sulphonation; halogenation; Friedel-Crafts reaction (alkylation and acylation); combustion; uses
Key points
- Aromatic means cyclic, planar, fully conjugated and holding (4n + 2) delocalised π electrons. 4n electrons in the same geometry means antiaromatic; a broken conjugation or a non-planar ring means non-aromatic.
- Kekulé's alternating-bond hexagon explains the formula, the single monosubstituted product and the three molecules of glyoxal from ozonolysis, but not the equal 139 pm bond lengths, the refusal to add bromine, or the low heat of hydrogenation.
- Benzene is a resonance hybrid of the two Kekulé forms, stabilised by a resonance energy of about 150 kJ mol⁻¹.
- Benzene is made by decarboxylating sodium benzoate with soda lime, reducing phenol with zinc dust, or passing ethyne through a red-hot tube.
- The typical reaction is electrophilic substitution in three steps: generate E⁺, slow attack by the π cloud to give the arenium ion, fast loss of H⁺ to restore aromaticity.
- Applied Chemistry
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The syllabus asks for
- Chemical industry and its importance
- Stages in producing a new product
- Economics of production; cash flow in the production cycle
- Running a chemical plant; designing a chemical plant
- Continuous and batch processing
- Environmental impact of the chemical industry
Key points
- The chemical industry converts cheap raw materials — air, brine, water, sulphur, limestone, hydrocarbons — into heavy, fine, speciality and pharmaceutical chemicals. Nepal imports 100% of its chemical fertilizer.
- New products pass through seven stages: market research → laboratory synthesis → pilot plant → process and plant design → construction and commissioning → full production → marketing and review, with a go/no-go decision at each.
- Costs are fixed capital and working capital, fixed costs and variable costs. Profit P = n(S-V) - F and the break-even output is nBE = F/(S-V).
- The cash-flow curve is negative through research and construction, reaches its minimum at start-up, and crosses zero at the end of the payback period.
- Plant design fixes the route, the conditions, the location, the materials of construction, energy integration and effluent treatment. Purification comes before every catalyst bed because catalysts are poisoned.
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The syllabus asks for
- Ammonia by Haber's process (principle and flow-sheet diagram)
- Nitric acid by Ostwald's process
- Sulphuric acid by contact process
- Sodium hydroxide by Diaphragm Cell
- Sodium carbonate by ammonia soda (Solvay) process
- Fertilizers: chemical fertilizers, types, production of urea with flow-sheet diagram
Key points
- Haber: N₂ + 3H₂ ⇌ 2NH₃, ΔH = −92.4 kJ mol⁻¹; Fe + Mo promoter, 450–500 °C, 200 atm, 1 : 3 feed; ammonia condensed out at −30 °C and unreacted gas recycled. Temperature is a compromise between yield and rate.
- Ostwald: 4NH₃ + 5O₂ → 4NO + 6H₂O over Pt–Rh gauze at 800 °C in ~10⁻³ s; 2NO + O₂ ⇌ 2NO₂ on cooling; 3NO₂ + H₂O → 2HNO₃ + NO in the absorber. Overall NH₃ + 2O₂ → HNO₃ + H₂O, giving 68% acid, concentrated with conc. H₂SO₄.
- Contact: S + O₂ → SO₂ (or 4FeS₂ + 11O₂ → 2Fe₂O₃ + 8SO₂); purify and dry; 2SO₂ + O₂ ⇌ 2SO₃ over V₂O₅ at 450 °C and 2 atm, ΔH = −196 kJ mol⁻¹; absorb in 98% H₂SO₄ to oleum (SO₃ + H₂SO₄ → H₂S₂O₇) and dilute. Low pressure suffices because conversion is already ~97%.
- Diaphragm cell: anode 2Cl⁻ → Cl₂ + 2e⁻, cathode 2H₂O + 2e⁻ → H₂ + 2OH⁻, overall 2NaCl + 2H₂O → 2NaOH + H₂ + Cl₂. The asbestos diaphragm plus a higher anolyte level keeps OH⁻ away from Cl₂. Cell liquor is 11% NaOH + 16% NaCl.
- Solvay: NaCl + NH₃ + CO₂ + H₂O → NaHCO₃↓ + NH₄Cl, then 2NaHCO₃ → Na₂CO₃ + H₂O + CO₂, with 2NH₄Cl + Ca(OH)₂ → CaCl₂ + 2NH₃ + 2H₂O recovering the ammonia. Overall 2NaCl + CaCO₃ → Na₂CO₃ + CaCl₂; CaCl₂ is the only waste.
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The paper
3hr, FM 75 written (+25 internal)
| Section | Questions | Marks each | Total |
|---|---|---|---|
| Group A MCQ | 11 | 1 | 11 |
| Group B short | 8 | 5 | 40 |
| Group C long | 3 | 8 | 24 |
Where the hours go
Teaching hours are the board's guide to how much of the paper each part carries.
- General and Physical Chemistry48 h
- Inorganic Chemistry35 h
- Organic Chemistry30 h
- Applied Chemistry15 h