Structure determination from reaction sequences

55 questions on Structure determination from reaction sequences from the Structural Identification and Practical Organic Chemistry chapter: 11 NEET level, 22 JEE Main, 22 JEE Advanced. Each one opens with its answer and solution.

• How many acyclic carbonyl compounds (aldehydes and ketones) of molecular formula C5H10O give a yellow precipitate with NaOH/I2? Count constitutional isomers onl... JEE Main level
• Benzene is treated with CH3COCl and anhydrous AlCl3 to give A, and A is heated with Zn-Hg/conc. HCl to give B. B is JEE Main level
• Ethanamide is heated with Br2 and aqueous KOH. The organic product is NEET level
• A hydrocarbon X (C6H10) adds two moles of H2 over Ni to give hexane and, on ozonolysis followed by Zn/H2O, gives two moles of ethanal and one mole of ethanedial... JEE Advanced level
• Select the correct conversion(s) from the following. JEE Advanced level
• Phenol is treated with NaOH, then with CO2 at 400 K and 4-7 atm, and the mixture is acidified to give A. A is warmed with ethanoic anhydride and a few drops of ... JEE Main level
• Which of the following alkenes give only one organic product on ozonolysis followed by Zn/H2O? JEE Advanced level
• A compound C9H10O gives an orange precipitate with 2,4-DNP, does not give a silver mirror with Tollens reagent and gives no yellow precipitate with NaOH/I2. Vig... JEE Advanced level
• A compound X (C9H10O) gives an orange precipitate with 2,4-DNP and a yellow precipitate with NaOH/I2, but does not reduce Tollens reagent. Vigorous oxidation of... JEE Advanced level
• An ester X (C4H8O2) is hydrolysed with aqueous NaOH to give a sodium salt Y and an alcohol Z. Z gives a yellow precipitate with NaOH/I2, and oxidation of Z with... JEE Advanced level
• Which of the following pairs of compounds can be distinguished by warming with NaOH/I2? JEE Advanced level
• A compound X (C6H10) is subjected to ozonolysis followed by Zn/H2O and gives a single product, OHC(CH2)4CHO. X is JEE Main level
• Phenol is treated with CHCl3 and aqueous NaOH at 340 K followed by acidification to give A (major product). A is heated with Zn-Hg/HCl to give B. B is JEE Advanced level
• In a Carius estimation, 0.400 g of an organic chloro compound gave 0.574 g of AgCl. Use atomic masses Ag = 108 and Cl = 35.5. The percentage of chlorine in the ... JEE Main level
• Ethanenitrile is treated with CH3MgBr in dry ether and the product is hydrolysed with dilute acid. The final organic product is JEE Main level
• The degree of unsaturation (number of rings plus pi bonds) of 4-nitrostyrene (1-ethenyl-4-nitrobenzene) is to be found from its molecular formula. Treat the nit... JEE Main level
• Ethanal is treated with CH3MgBr followed by H3O+ to give A. A is oxidised with PCC to give B, and B is warmed with NaOH/I2. Besides yellow iodoform, the organic... JEE Main level
• Bromobenzene is stirred with magnesium in dry ether to give A. A reacts with methanal and the product is hydrolysed with dilute acid to give B. B is JEE Main level
• How many alcohols of molecular formula C5H12O give a yellow precipitate with NaOH/I2? Count constitutional isomers only (no stereoisomers). JEE Main level
• Aniline is treated with CH3COCl in pyridine to give A, A is brominated with Br2 in ethanoic acid to give B (major monobromo product), and B is hydrolysed with a... JEE Main level
• Toluene is treated with CrO2Cl2 in CS2 followed by hydrolysis to give A. A is heated with concentrated aqueous NaOH. The organic products are JEE Main level
• Methanal reacts with CH3MgBr in dry ether and the adduct is then treated with dilute acid. The product is NEET level
• Benzene is treated with CH3Cl in the presence of anhydrous AlCl3 to give A. A is heated with alkaline KMnO4 and then acidified to give B. B is NEET level
• Ethanal is warmed with dilute NaOH to give A, and A is heated to give B by loss of water. B is JEE Main level
• How many primary amines are there among the constitutional isomers of C4H11N (all of which are saturated acyclic amines)? Each of them gives the carbylamine tes... JEE Main level
• Methanal is treated with CH3CH2MgBr followed by H3O+ to give A. A reacts with PBr3 to give B, B with KCN to give C, and C is hydrolysed with aqueous acid to giv... JEE Advanced level
• Aniline is treated with NaNO2/HCl at 273 K to give A, and A is warmed with CuCN to give B. B is NEET level
• Nitrobenzene is reduced with Sn/HCl and the product, after neutralisation, is warmed with chloroform and alcoholic KOH. The final product, which has a very unpl... NEET level
• Aromatic hydrocarbons of formula C8H10 that contain a benzene ring are oxidised with hot alkaline KMnO4 and then acidified. How many of the isomers give a benze... JEE Main level
• Consider the four constitutional isomeric alcohols of formula C4H10O (stereoisomers are ignored). Select the correct statement(s). JEE Advanced level
• 4-Nitrotoluene is reduced with Sn/HCl to give A. A is treated with NaNO2/HCl at 273 K to give B. B is warmed with CuBr/HBr to give C, and C is heated with alkal... JEE Advanced level
• A compound C3H6O gives an orange precipitate with 2,4-DNP, gives a yellow precipitate with NaOH/I2 and does not reduce Tollens reagent. The compound is NEET level
• A compound X (C8H8O) gives an orange precipitate with 2,4-DNP, gives a yellow precipitate with NaOH/I2 and does not reduce Tollens reagent. Clemmensen reduction... JEE Advanced level
• A compound C2H6O liberates hydrogen with sodium and on oxidation with excess acidified K2Cr2O7 gives a compound C2H4O2. The compound is NEET level
• Propanal is treated with CH3MgBr and then H3O+ to give A. A is heated with concentrated H2SO4 to give the major alkene B. B is subjected to ozonolysis followed ... JEE Advanced level
• A hydrocarbon C5H10 undergoes ozonolysis followed by Zn/H2O to give ethanal and propanone. The hydrocarbon is JEE Main level
• Ethyl ethanoate is treated with excess CH3MgBr in dry ether and then H3O+ to give A (along with ethanol). A is heated with concentrated H2SO4 to give B, and B i... JEE Advanced level
• Among the amines of formula C3H9N, the one that does not give the carbylamine test and reacts with benzenesulfonyl chloride to give a product insoluble in aqueo... JEE Main level
• A hydrocarbon C5H8 gives a white precipitate with ammoniacal AgNO3 and adds two moles of H2 over Ni to give unbranched pentane. The hydrocarbon is JEE Main level
• An organic compound gives a silver mirror with Tollens reagent, does not reduce Fehling solution and, when treated with concentrated NaOH, gives an alcohol and ... NEET level
• Phenol is treated with chloroform and aqueous NaOH at 340 K and the mixture is then acidified (Reimer-Tiemann reaction). The major product is NEET level
• Bromoethane is heated with alcoholic KCN to give A. A is refluxed with dilute HCl to complete hydrolysis, giving B. B is NEET level
• Which of the following amines give both a positive carbylamine test and an orange-red dye when diazotised with NaNO2/HCl at 273 K and then coupled with alkaline... JEE Advanced level
• Propene is treated with HBr in the presence of a peroxide to give A. A reacts with alcoholic KCN to give B, and B is reduced with LiAlH4 to give C. C is JEE Main level
• Ethanamine is treated with NaNO2/HCl at 273 K to give A, and A is oxidised with PCC to give B. B is JEE Main level
• An alkene C4H8 is treated with O3 followed by Zn/H2O and gives only one organic product, ethanal. The alkene is NEET level
• Benzene is treated with CH3COCl/AlCl3 to give A. A is heated with NaOH/Br2 (excess) and acidified to give B. B is treated with SOCl2 to give C, C with excess NH... JEE Advanced level
• Aniline is treated with excess bromine water to give A. A is treated with NaNO2/HCl at 273 K to give B, and B is treated with hypophosphorous acid (H3PO2) to gi... JEE Advanced level
• Benzenediazonium chloride is treated with different reagents. Select the correct product(s). JEE Advanced level
• A compound X (C4H8O) gives an orange precipitate with 2,4-DNP, a yellow precipitate with NaOH/I2 and no silver mirror with Tollens reagent. Select the correct s... JEE Advanced level
• Which of the following aldehydes give the Cannizzaro reaction on heating with concentrated aqueous NaOH? JEE Advanced level
• Potassium phthalimide is heated with bromoethane to give A, and A is heated with aqueous NaOH to give B and disodium phthalate. B is JEE Main level
• Benzaldehyde is treated with CH3MgBr and then H3O+ to give A. A is oxidised with PCC to give B. Select the correct statement(s). JEE Advanced level
• Ethyne is treated with NaNH2 and then with CH3I to give A. A is treated with dilute H2SO4 containing HgSO4 to give B. B is JEE Main level
• Propyne is treated with NaNH2 and then with CH3CH2Br to give A. A is partially hydrogenated with H2 and Lindlar catalyst to give B. B is subjected to ozonolysis... JEE Advanced level