What the board asks
We went through the ISC board papers, question by question, and matched each question to a topic. Here is what was asked, how often, and what was never asked.
Chemistry: 384 topics in the 2027 syllabus, across 10 units. The board has asked 252 of them at least once. 132 were never asked in the papers we checked.
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C8 Aldehydes, Ketones and Carboxylic Acids
All the topics in Chemistry: Aldehydes, Ketones and Carboxylic Acids
Asked topics first, the most asked at the top. Tap a topic to see what to write, the result, the years, and the real board questions.
63 topics shown
| # | Topic | Type | Marks | Times asked | Last asked | Status |
|---|---|---|---|---|---|---|
| 1 | Identify A, B, C, D in a given reagent chainWork through the chain arrow by arrow and write the structure and name of each lettered compound (for example ethyne to acetaldehyde to acetic acid to acetyl chloride, or acid to acid chloride to aldehyde to calcium salt to ketone). | Conversion | 2 | 7 papers | Specimen 2027 | Asked |
| 2 | Identify compounds from formula and test results (case problem)From a molecular formula and clues (Fehling, Tollens, iodoform, aldol, Cannizzaro, NaHCO3, ozonolysis, soda lime) deduce and write the structures of all lettered compounds and the equations the question asks for. | Conversion | 5 | 7 papers | Specimen 2027 | Asked |
| 3 | Cannizzaro reaction: disproportionation of aldehydes without alpha-HWrite the equation for HCHO or benzaldehyde with concentrated NaOH giving the alcohol and the sodium salt of the acid, name the products and state that it needs no alpha-H; include the crossed Cannizzaro with HCHO. | Reaction | 1 | 5 papers | Specimen 2027 | Asked |
| 4 | Distinguish aldehydes from ketones (and from alcohols)Name a test (Tollens silver mirror, Fehling red precipitate or Schiff pink colour) with reagent, condition and the observation for each compound of the pair, including pairs such as ethanol and ethanal. | Tell apart (test) | 1 | 5 papers | Specimen 2027 | Asked |
| 5 | Acid chlorides and anhydrides from carboxylic acidsWrite equations for a carboxylic acid with PCl5, PCl3 and SOCl2 giving the acid chloride (with by-products), and heating with P2O5 giving the anhydride. | Reaction | 1 | 5 papers | Specimen 2027 | Asked |
| 6 | Dry distillation of calcium salts of carboxylic acidsWrite the equation for heating dry calcium acetate (ketone), and calcium acetate with calcium formate (aldehyde), naming the product. | Reaction | 1 | 5 papers | 2026 | Asked |
| 7 | Clemmensen reduction: C=O to CH2Write the equation for an aldehyde or ketone with zinc amalgam and conc. HCl giving the alkane, and name the reaction. | Reaction | 1 | 5 papers | 2026 | Asked |
| 8 | Rosenmund reduction: acid chloride to aldehydeWrite the equation for an acid chloride with H2 over Pd on BaSO4 poisoned with sulphur or quinoline in boiling xylene, giving the aldehyde, and state why the catalyst is poisoned. | Reaction | 1 | 5 papers | 2025 improvement | Asked |
| 9 | Iodoform reaction: equation and which compounds respondWrite the balanced iodoform equation with I2 and NaOH (yellow CHI3) for acetaldehyde or a methyl ketone, and pick out from a list which compounds give it (CH3CO- or CH3CH(OH)- group). | Reaction | 1 | 4 papers | Specimen 2027 | Asked |
| 10 | Aldol condensation: aldol and its dehydrationWrite the equation for acetaldehyde (or acetone) with dilute NaOH giving the aldol, then on heating the alpha,beta-unsaturated carbonyl compound, naming both products. | Reaction | 1 | 4 papers | Specimen 2027 | Asked |
| 11 | Convert one compound to another in two or three stepsWrite the sequence of balanced equations with reagent and conditions over each arrow (for example acetaldehyde to acetone, acetone to propene, benzaldehyde to benzene, benzoic acid to benzaldehyde, methyl chloride to acetic acid, benzaldehyde to cinnamic acid). | Conversion | 1 | 4 papers | Specimen 2027 | Asked |
| 12 | Esterification and amides from carboxylic acidsWrite the reversible esterification of an acid with an alcohol and conc. H2SO4 (name the ester), and the formation of the amide by heating the ammonium salt (or acid chloride with NH3). | Reaction | 1 | 4 papers | 2026 | Asked |
| 13 | Ozonolysis of alkenes to aldehydes and ketonesWrite the ozonide step (O3) and its cleavage with Zn/H2O, giving the carbonyl products, and work backwards from products to place the C=C in the alkene. | Reaction | 1 | 3 papers | Specimen 2027 | Asked |
| 14 | Hydration of alkynes to acetaldehyde and ketonesWrite the equation for ethyne or propyne with dilute H2SO4 and HgSO4 at about 333 K, showing the enol that tautomerises to the carbonyl compound. | Reaction | 1 | 3 papers | Specimen 2027 | Asked |
| 15 | Reduction to alcohols: LiAlH4, NaBH4, H2/NiWrite the reduction of an aldehyde to a primary alcohol and a ketone to a secondary alcohol, with the reagent over the arrow. | Reaction | 1 | 3 papers | Specimen 2027 | Asked |
| 16 | Carboxylic acids from alcohols and aldehydes by oxidationWrite the oxidation of a primary alcohol or aldehyde (aliphatic and aromatic: benzyl alcohol, benzaldehyde) to the acid with acidified K2Cr2O7 or alkaline KMnO4 followed by acid. | Reaction | 1 | 3 papers | Specimen 2027 | Asked |
| 17 | Hell-Volhard-Zelinsky (HVZ) reaction: alpha-halogenationWrite the equation for a carboxylic acid with Cl2 or Br2 and red phosphorus giving the alpha-halo acid, and for excess Cl2 the di- and trichloro acids, naming the reaction. | Reaction | 1 | 3 papers | Specimen 2027 | Asked |
| 18 | Tests for formic, acetic and benzoic acidsGive a test with reagent and observation that identifies each acid or separates it from a given compound (all: brisk effervescence with NaHCO3; formic: reduces Tollens and Fehling; acetic: red colour with neutral FeCl3; benzoic: buff precipitate with neutral FeCl3), and state what the other compound does. | Tell apart (test) | 1 | 3 papers | 2026 | Asked |
| 19 | Oxidation of aldehydes and ketones; Tollens and Fehling reactionsWrite the oxidation of an aldehyde to the acid with K2Cr2O7/H2SO4, Tollens reagent (silver mirror) and Fehling solution (red Cu2O), and the oxidation of a ketone with strong oxidants to a mixture of smaller acids. | Reaction | 1 | 3 papers | 2025 improvement | Asked |
| 20 | Decarboxylation with soda limeWrite the equation for the sodium salt of a carboxylic acid heated with soda lime (NaOH + CaO) giving the hydrocarbon with one carbon less, including benzoate to benzene. | Reaction | 1 | 3 papers | 2025 | Asked |
| 21 | Ammonia derivatives: oxime, hydrazone, phenylhydrazoneWrite the addition-elimination equations of an aldehyde or ketone with NH2OH, NH2NH2 and C6H5NHNH2, losing water, and name each product. | Reaction | 1 | 3 papers | 2024 | Asked |
| 22 | Carboxylic acids from Grignard reagent and CO2Write the addition of RMgX to dry ice (CO2) and acid hydrolysis of the salt to the carboxylic acid. | Reaction | 1 | 2 papers | Specimen 2027 | Asked |
| 23 | Acidity of aliphatic acids: effect of substituentsArrange given aliphatic acids in order of acid strength and give the reason: electron-withdrawing groups (-I: Cl, F, NO2) stabilise the carboxylate ion, electron-releasing alkyl groups (+I) destabilise it; effect falls with distance and rises with number of groups. | Comparison | 1 | 2 papers | Specimen 2027 | Asked |
| 24 | IUPAC names and structures of aldehydes and ketonesGiven a structure write the IUPAC name (longest chain with C=O, -al or -one, lowest locant to C=O, substituent locants), or draw the structure from a name or a common name. | Structure or name | 1 | 2 papers | 2026 | Asked |
| 25 | Addition of HCN: cyanohydrin and its hydrolysisWrite the equation for an aldehyde or ketone with HCN (base catalysed) giving the cyanohydrin, and its acid hydrolysis to the 2-hydroxy acid, naming both. | Reaction | 1 | 2 papers | 2026 | Asked |
| 26 | Benzaldehyde: oxidation, reduction, HCN, NaHSO3, ammonia derivativesWrite equations for benzaldehyde oxidised (Tollens, KMnO4) to benzoic acid, reduced to benzyl alcohol, and its addition of HCN and NaHSO3 and condensation with NH2OH, NH2NH2 and C6H5NHNH2, naming the products. | Reaction | 1 | 2 papers | 2025 improvement | Asked |
| 27 | Carboxylic acids by hydrolysis of nitrilesWrite the acid (or alkaline then acid) hydrolysis of a nitrile through the amide to the carboxylic acid, including making the nitrile from an alkyl halide with KCN to step up one carbon. | Reaction | 1 | 2 papers | 2024 | Asked |
| 28 | Benzoin condensationWrite the equation for two molecules of benzaldehyde with alcoholic KCN (ethanolic NaCN) on warming to give benzoin, with its structure and formula C14H12O2. | Reaction | 1 | 2 papers | 2023 | Asked |
| 29 | Distinguish aromatic and aliphatic aldehydesGive Fehling test (aliphatic aldehyde gives red precipitate, benzaldehyde does not) or iodoform test for acetaldehyde, with reagent and observation for both compounds. | Tell apart (test) | 1 | 2 papers | 2019 | Asked |
| 30 | Stephen reaction: nitrile to aldehydeWrite the equation for a nitrile reduced with SnCl2 and HCl to the imine (as its salt), then hydrolysed with water to the aldehyde. | Reaction | 1 | 1 paper | Specimen 2027 | Asked |
| 31 | Grignard reagent with carbonyl compounds to alcoholsWrite the addition of RMgX to HCHO, another aldehyde or a ketone and the hydrolysis, and say which gives a primary, secondary or tertiary alcohol. | Reaction | 1 | 1 paper | Specimen 2027 | Asked |
| 32 | Perkin reaction: benzaldehyde to cinnamic acidWrite the equation for benzaldehyde heated with acetic anhydride and sodium acetate, then hydrolysis, giving cinnamic acid, and name the reaction. | Reaction | 1 | 1 paper | Specimen 2027 | Asked |
| 33 | Wolff-Kishner reduction: hydrazone with KOH in glycolWrite the two steps: the carbonyl compound with hydrazine to the hydrazone, then heating with KOH in ethylene glycol to the alkane and N2, and name the reaction. | Reaction | 1 | 1 paper | 2025 | Asked |
| 34 | Cross aldol condensation: products from two carbonyl compoundsWrite the cross aldol between two different carbonyl compounds, listing all four products when both have alpha-H, or the single product when one (such as benzaldehyde or HCHO) has none. | Reaction | 1 | 1 paper | 2025 improvement | Asked |
| 35 | Acids with metals, alkalis, carbonates and bicarbonatesWrite equations for a carboxylic acid with Na, NaOH, Na2CO3 and NaHCO3, naming the gas evolved, and use brisk effervescence with NaHCO3 as evidence of a COOH group. | Reaction | 1 | 1 paper | 2025 improvement | Asked |
| 36 | Kolbe electrolytic reactionWrite the overall equation for electrolysis of aqueous sodium or potassium salt of a carboxylic acid giving the alkane (2R), CO2 at the anode and H2 and NaOH at the cathode, with the electrode reactions if asked. | Reaction | 1 | 1 paper | 2025 improvement | Asked |
| 37 | From alcohols: oxidation and dehydrogenation to aldehydes and ketonesWrite equations for oxidation of a primary alcohol to an aldehyde and a secondary alcohol to a ketone (K2Cr2O7/H2SO4, or Cu at 573 K), and give the reason the aldehyde must be distilled out as it forms. | Reaction | 1 | 1 paper | 2024 | Asked |
| 38 | Reactivity order towards nucleophilic addition, with reasonsArrange given carbonyl compounds in order of reactivity and give the reasons: electron-releasing alkyl groups and the benzene ring (resonance) reduce the positive charge on carbon, and bulky groups hinder attack. | Comparison | 1 | 1 paper | 2024 | Asked |
| 39 | Benzaldehyde: state, smell, stability and usesState that benzaldehyde is a colourless oily liquid with the smell of bitter almonds that slowly oxidises in air to benzoic acid, and give its uses (flavouring, perfumes, dyes, making cinnamic acid). | Statement | 1 | 1 paper | 2024 | Asked |
| 40 | Reaction with ammonia: urotropine and aldehyde ammoniaWrite the equation for formaldehyde with ammonia giving hexamethylenetetramine (urotropine), and for acetaldehyde with ammonia giving the aldimine, with one use of urotropine. | Reaction | 1 | 1 paper | 2023 | Asked |
| 41 | Addition of sodium bisulphite and its useWrite the equation for an aldehyde or methyl ketone with NaHSO3 giving the crystalline bisulphite adduct, and state that dilute acid or alkali regenerates the carbonyl compound, so it is used for separation and purification. | Reaction | 1 | 1 paper | 2018 | Asked |
| 42 | Acidity of alpha-hydrogen; which compounds can form enolatesExplain why an alpha-hydrogen is acidic (the carbanion is stabilised by resonance as the enolate), and use its presence or absence to say whether a compound gives aldol or Cannizzaro reaction. | Give reason | 1 | 1 paper | 2018 | Asked |
| 43 | Structure and polarity of the carbonyl groupDescribe the C=O group: sp2 carbon, trigonal planar with about 120 degree angles, one sigma and one pi bond, polar with partial positive carbon and partial negative oxygen, and say this makes the carbon open to nucleophiles. | Statement | 1 | never | Never asked | |
| 44 | Acid chloride with dialkyl cadmium to ketoneWrite the preparation of the dialkyl cadmium from a Grignard reagent and CdCl2, then its reaction with an acid chloride to give the ketone. | Reaction | 1 | never | Never asked | |
| 45 | Nitrile with Grignard reagent to ketoneWrite the addition of RMgX to the nitrile to give the imine salt, then acid hydrolysis to the ketone. | Reaction | 1 | never | Never asked | |
| 46 | From esters: partial reduction to aldehydesWrite the reduction of an ester with DIBAL-H at low temperature followed by water to give the aldehyde and the alcohol. | Reaction | 1 | never | Never asked | |
| 47 | State and boiling points of aldehydes and ketonesState that HCHO is a gas and lower members are liquids, and compare boiling points with alkanes, ethers and alcohols of similar mass, giving dipole-dipole forces and lack of H-bonding as the reasons. | Comparison | 1 | never | Never asked | |
| 48 | Mechanism of nucleophilic addition (HCN as example)Show with curved arrows the nucleophile attacking the carbonyl carbon to give a tetrahedral alkoxide, then protonation; for HCN show the base generating CN- first. | Mechanism | 2 | never | Never asked | |
| 49 | Reduction with red phosphorus and HI to alkanesWrite the equation for an aldehyde or ketone heated with HI and red phosphorus giving the alkane, with I2 and water as by-products. | Reaction | 1 | never | Never asked | |
| 50 | Mechanism of aldol condensationShow with curved arrows: OH- removes an alpha-H to give the enolate, the enolate attacks the C=O of a second molecule, the alkoxide takes H+ from water to give the aldol, and then loss of water on heating. | Mechanism | 2 | never | Never asked | |
| 51 | Mechanism of Cannizzaro reaction (hydride transfer)Show with curved arrows: OH- adds to the C=O, the tetrahedral anion transfers a hydride ion to a second aldehyde molecule, then the proton exchange that gives the carboxylate and the alcohol. | Mechanism | 2 | never | Never asked | |
| 52 | Distinguish formaldehyde and acetaldehydeName a test that one gives and the other does not (iodoform: acetaldehyde gives yellow CHI3, formaldehyde does not), with reagent, condition and observation for each. | Tell apart (test) | 1 | never | Never asked | |
| 53 | Uses of aldehydes and ketonesState one or two uses each of formaldehyde (formalin as preservative, urotropine, bakelite), acetaldehyde and acetone (solvent, nail-polish remover). | Statement | 1 | never | Never asked | |
| 54 | Etard reaction: toluene to benzaldehyde with chromyl chlorideWrite the equation for toluene with chromyl chloride in CS2 giving the chromium complex, then hydrolysis to benzaldehyde, and name it as the Etard reaction. | Reaction | 1 | never | Never asked | |
| 55 | Carbonyl compounds with PCl5: gem-dichloridesWrite the equation for benzaldehyde (or acetaldehyde, acetone) with PCl5 giving the gem-dichloride and POCl3, naming the product. | Reaction | 1 | never | Never asked | |
| 56 | Electrophilic substitution in benzaldehyde (meta products)Write equations for nitration (conc HNO3 + conc H2SO4), halogenation (Cl2/FeCl3) and sulphonation of benzaldehyde giving the meta product, and give the reason CHO is deactivating and meta directing. | Reaction | 1 | never | Never asked | |
| 57 | Carboxylic acids: classification, structure, IUPAC namesClassify given acids as mono or dicarboxylic, aliphatic or aromatic, give examples with formulae (formic, acetic, oxalic, malonic, succinic, benzoic, phthalic), name them by IUPAC, and draw the resonance of the COOH group. | Structure or name | 1 | never | Never asked | |
| 58 | Physical properties of acids: state, boiling point, solubilityCompare boiling points of carboxylic acids with alcohols, aldehydes and ketones of similar mass, explaining dimer formation by hydrogen bonding, and explain solubility in water falling with chain length. | Comparison | 1 | never | Never asked | |
| 59 | Acidity of benzoic acids, phenol and alcohols comparedArrange acids such as benzoic, substituted benzoic (NO2, Cl, CH3, OCH3), acetic, formic acids, phenol and ethanol in order of acid strength, giving resonance stabilisation of the carboxylate and the effect of each substituent. | Comparison | 1 | never | Never asked | |
| 60 | Benzoic acid: meta nitration and sulphonationWrite equations for nitration and sulphonation of benzoic acid giving the meta products, and explain why -COOH is deactivating and meta directing and why benzoic acid does not undergo Friedel-Crafts reaction. | Reaction | 1 | never | Never asked | |
| 61 | Uses of formic, acetic and benzoic acidsState one or two uses of each: formic acid (leather tanning, coagulating rubber latex), acetic acid (vinegar, solvent, making esters), benzoic acid (sodium benzoate as food preservative, medicine). | Statement | 1 | never | Never asked | |
| 62 | Give reasons and assertion-reason items across the unitFor each statement give the reason in one or two lines (or judge assertion and reason and whether the reason explains the assertion), on items such as: HCHO has no aldol, carboxylic acids do not give typical carbonyl reactions, acids boil higher than alcohols, benzaldehyde does not reduce Fehling, ketones resist oxidation. | Give reason | 1 | never | Never asked | |
| 63 | Benzene to toluene to benzoic acid chainWrite Friedel-Crafts methylation of benzene (CH3Cl, anhydrous AlCl3) to toluene, then side-chain oxidation (K2Cr2O7/H2SO4 or alk KMnO4) to benzoic acid, identifying each compound. | Conversion | 1 | 2 papers | 2024 | Not in syllabus |
This list was made from the 2027 syllabus and checked with 9 board papers, including the 2027 specimen paper. It is not yet checked with the textbook.
The 10 topics Chemistry papers ask most
Counted on the board papers from 2018 to the 2027 specimen paper, which every unit has been checked against.
- 1.IUPAC names of coordination compounds from formulaC5 Coordination Compounds · asked 8 times since 2018
- 2.Faraday's first law: mass, charge, current or timeC2 Electrochemistry · asked 7 times since 2018
- 3.Give reasons: transition metal ions are coloured, some colourlessC4 d- and f-Block Elements · asked 7 times since 2018
- 4.Alcohols from Grignard reagent: 1, 2, 3 degreeC7 Alcohols, Phenols and Ethers · asked 7 times since 2018
- 5.Williamson's synthesis of ethersC7 Alcohols, Phenols and Ethers · asked 7 times since 2018
- 6.Identify A, B, C, D in a given reagent chainC8 Aldehydes, Ketones and Carboxylic Acids · asked 7 times since 2018
- 7.Identify compounds from formula and test results (case problem)C8 Aldehydes, Ketones and Carboxylic Acids · asked 7 times since 2018
- 8.Identify A, B, C: amide, Hoffmann and amine-test chainsC9 Organic Compounds containing Nitrogen · asked 7 times since 2018
- 9.Gibbs energy and maximum work from cell emfC2 Electrochemistry · asked 6 times since 2018
- 10.Coordination number and oxidation state of the central metalC5 Coordination Compounds · asked 6 times since 2018