Carboxylic acids: acidity, preparation, derivatives, HVZ reaction

55 questions on Carboxylic acids: acidity, preparation, derivatives, HVZ reaction from the Aldehydes, Ketones and Carboxylic Acids chapter: 11 NEET level, 22 JEE Main, 22 JEE Advanced. Each one opens with its answer and solution.

• Propanenitrile, CH3CH2CN, is refluxed with dilute hydrochloric acid for a long time. The organic product is NEET level
• Phenylmagnesium bromide, C6H5MgBr, in dry ether is poured over solid CO2 and the product is then treated with dilute HCl. The organic product is NEET level
• Use pKa values: formic acid 3.75, ethanoic acid 4.76, benzoic acid 4.20, chloroethanoic acid 2.86. The strongest acid among these is NEET level
• Sodium ethanoate is heated strongly with soda lime (NaOH + CaO). The hydrocarbon formed is NEET level
• Methylbenzene is heated under reflux with alkaline KMnO4 and the mixture is then acidified. The organic product is NEET level
• Propanoic acid is warmed with Br2 and a little red phosphorus, and the mixture is then treated with water. The main product is NEET level
• Ethanoic acid is treated with excess LiAlH4 in dry ether, followed by dilute acid work-up. The organic product is NEET level
• Towards nucleophilic acyl substitution the correct order of decreasing reactivity of ethanoyl derivatives is NEET level
• Ethanoic acid is warmed with thionyl chloride. The products are NEET level
• A concentrated aqueous solution of sodium ethanoate is electrolysed. The main organic product formed at the anode is NEET level
• Ethanamide is heated with phosphorus pentoxide, P2O5. The organic product is NEET level
• Ethanoic acid is heated with ethanol labelled as CH3CH2^18OH in the presence of conc. H2SO4. Assuming the usual acyl-oxygen cleavage mechanism of Fischer esteri... JEE Main level
• Which of the following correctly arranges the acids in decreasing order of acidity? (pKa: CH3COOH 4.76, ClCH2COOH 2.86, Cl2CHCOOH 1.29, Cl3CCOOH 0.65) JEE Main level
• The pKa of 2-chlorobutanoic acid is 2.84 and that of 4-chlorobutanoic acid is 4.52. How many times larger is the acid dissociation constant of 2-chlorobutanoic ... JEE Main level
• Given pKa values: o-nitrobenzoic acid 2.17, m-nitrobenzoic acid 3.45, p-nitrobenzoic acid 3.44, benzoic acid 4.20. The ortho isomer is far stronger than the met... JEE Main level
• Which of the following is the most reactive towards hydrolysis by cold water? JEE Main level
• Propanoyl chloride is treated with sodium azide to form propanoyl azide, which is then heated in an inert solvent and the product is boiled with water. The fina... JEE Main level
• Dry silver butanoate, CH3CH2CH2COOAg, is refluxed with bromine in CCl4. The organic product is JEE Main level
• 3-Oxobutanoic acid, CH3COCH2COOH, is gently warmed to about 100 degC. The organic product is JEE Main level
• Propanedioic acid (malonic acid) is heated just above its melting point (about 140 degC). The organic product is JEE Main level
• 4-Nitrobenzoic acid is treated with diborane (B2H6) in THF and then hydrolysed with water. The product is JEE Main level
• 1-(4-Methylphenyl)ethanone, p-CH3-C6H4-COCH3, is treated with excess I2 and aqueous NaOH, warmed, and then acidified. The carboxylic acid formed is JEE Main level
• Ethyl ethanoate is heated with excess aqueous NaOH. The products are JEE Main level
• In the acid-catalysed esterification of ethanoic acid with methanol, the first step of the mechanism is JEE Main level
• A mixture of benzoic acid, phenol and methylbenzene in ether is shaken with aqueous NaHCO3. (pKa values: benzoic acid 4.20, phenol 10.0, carbonic acid about 6.4... JEE Main level
• Given pKa values: p-methoxybenzoic acid 4.47, p-toluic acid 4.37, benzoic acid 4.20, p-nitrobenzoic acid 3.44. The correct order of increasing acid strength is JEE Main level
• Ethanoyl chloride is added to a solution of anhydrous sodium ethanoate. The main organic product is JEE Main level
• Ethanoic acid reacts with phosphorus pentachloride. Which set lists all the products? JEE Main level
• Which of the following correctly give propanoic acid (after acidification where needed)? JEE Main level
• Which of the following reagents convert ethanoic acid into ethanoyl chloride? JEE Main level
• Which of the following acids lose CO2 readily on simple warming to about 100-150 degC? JEE Main level
• Benzoic acid is treated separately with the following. Select the correct statements. JEE Main level
• Use pKa values: 2-chlorobutanoic acid 2.84, 3-chlorobutanoic acid 4.06, 4-chlorobutanoic acid 4.52, o-nitrobenzoic acid 2.17, p-nitrobenzoic acid 3.44, m-nitrob... JEE Main level
• Bromoethane is treated successively with (i) KCN in ethanol, (ii) dilute H2SO4 under reflux, (iii) Br2 with a little red phosphorus, then H2O, and (iv) excess N... JEE Advanced level
• Propanoic acid is treated with Br2 and red phosphorus, then H2O; the product is boiled with excess aqueous KOH and then acidified. The final organic product is JEE Advanced level
• Ethyl 3-oxobutanoate is treated with one equivalent of sodium ethoxide and then one equivalent of bromoethane; the product is heated with dilute aqueous NaOH, t... JEE Advanced level
• Diethyl propanedioate is treated with one equivalent of NaOEt and one equivalent of CH3I, then again with one equivalent of NaOEt and one equivalent of CH3CH2Br... JEE Advanced level
• Ethanoic acid is heated with methanol labelled as CH3^18OH in the presence of conc. H2SO4 to give ester X. X is then completely hydrolysed with excess aqueous N... JEE Advanced level
• Assertion (A): o-Nitrobenzoic acid (pKa 2.17) is a stronger acid than p-nitrobenzoic acid (pKa 3.44). Reason (R): The -I effect of the nitro group falls off wit... JEE Advanced level
• Ethanoic anhydride is treated with exactly two equivalents of methylamine, CH3NH2, in an inert solvent. The products are JEE Advanced level
• Compound A (C2H4O2) liberates CO2 from aqueous NaHCO3. A reacts with SOCl2 to give B; B reacts with excess NH3 to give C; C is heated with P2O5 to give D; D is ... JEE Advanced level
• 0.900 g of an acyclic saturated dicarboxylic acid is exactly neutralised by 20.0 mL of 1.00 M aqueous NaOH. The acid is (take C = 12, H = 1, O = 16) JEE Advanced level
• Equimolar amounts of sodium ethanoate and sodium propanoate in concentrated aqueous solution are electrolysed (Kolbe). How many different hydrocarbons are forme... JEE Advanced level
• Hexanedioic acid is heated with Ba(OH)2 at about 300 degC, and the organic product is reduced with NaBH4 followed by aqueous work-up. The final product is JEE Advanced level
• 1,4-Dimethylbenzene is heated with excess alkaline KMnO4 and acidified. The product is refluxed with excess SOCl2 and then treated with excess NH3. The final or... JEE Advanced level
• 4-Methoxy-4-oxobutanoic acid, CH3OCO-CH2CH2-COOH, is treated in separate experiments with (X) B2H6 in THF followed by water, and (Y) excess LiAlH4 followed by a... JEE Advanced level
• Propanoic acid is heated with one equivalent of Br2 and red phosphorus, then treated with H2O; the product is warmed with excess aqueous KOH and the solution is... JEE Advanced level
• 1.00 mol of ethanoic acid and 2.00 mol of ethanol react in a rigid vessel at constant temperature to equilibrium: CH3COOH + C2H5OH <=> CH3COOC2H5 + H2O, with K_... JEE Advanced level
• 24.4 g of benzoic acid is converted to aniline by the Schmidt reaction (C6H5COOH + HN3 -> C6H5NH2 + CO2 + N2) with an overall yield of 80 %. Calculate the mass ... JEE Advanced level
• Which of the following give benzoic acid on suitable treatment (heating with the reagent, then acidification where relevant)? JEE Advanced level
• Complete hydrolysis with dilute aqueous acid and heat gives ethanoic acid as the only carboxylic acid from which of the following? JEE Advanced level
• Butanoic acid is heated with one equivalent of Br2 and a little red phosphorus, followed by water. Select the correct statements. JEE Advanced level
• Ethyl ethanoate is subjected to the following reactions. Select the correct statements. JEE Advanced level
• Select the correct statements about decarboxylative reactions of sodium or silver butanoate. JEE Advanced level
• Carbonic acid has pKa1 of about 6.4. Which of the following acids liberate CO2 when added to aqueous NaHCO3? (pKa: ethanoic acid 4.76, phenol 10.0, trichloroeth... JEE Advanced level