Free Carboxylic Acids MCQs with Answers
550 Carboxylic Acids MCQs from Chemistry, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Carboxylic acids are named and studied through the combined effects of the carbonyl and hydroxyl groups, their preparation, acidity and hydrogen bonding. Reactions include neutralisation, esterification, reduction and conversion into acid chlorides, anhydrides, esters and amides, with emphasis on how these derivatives interconvert.
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Read the Carboxylic Acids notesFree MDCAT chapter notes with key terms550 questions · page 8 of 28
- A. Alcohol
- B. Alcoholic potassium cyanide
- C. Potassium cyanide
- D. Water
Explanation: Alkane nitriles are prepared by the nucleophilic substitution (SN2) reaction of an alkyl halide with a cyanide salt.
Correct answer: Alcoholic potassium cyanide- A. CH3CH2NH2
- B. CH3CONH2
- C. NH2CONH2
- D. CH3COOH
Explanation: The acid-catalyzed hydrolysis of a nitrile proceeds in two stages. The first stage produces an amide as an intermediate (A = acetamide…
Correct answer: CH3CONH2- A. H-atom of R group
- B. Carbonyl group
- C. H-atom of OH group
- D. Carboxyl group
Explanation: The reaction with a base like a carbonate involves the acidic proton of the carboxylic acid.
Correct answer: H-atom of OH group- A. Electrophilic substitution
- B. Nucleophilic addition
- C. Nucleophilic acyl substitution
- D. Oxidation
Explanation: This describes a key step in the Fischer esterification mechanism. The alcohol acts as a nucleophile, attacking the protonated carbonyl…
Correct answer: Nucleophilic acyl substitution- A. CH3CHClCH2COOH
- B. CH3CH2CCl2COOH
- C. CH3CH2CHClCOOH
- D. CH3CH2CH2COOH
Explanation: The acidity of carboxylic acids increases with the presence of electron-withdrawing groups (like-CI) near the -COOH group.
Correct answer: CH3CH2CCl2COOH- A. Displacement of the -H from the acid by -Cl
- B. Displacement of the -OH from the acid by -NH2
- C. Attachment of -NH2 with the carbonyl oxygen
- D. Displacement of the -H from the acid by -NH2
Explanation: The overall transformation involves replacing the hydroxyl (-OH) group of the carboxylic acid with an amino (-NH2) group.
Correct answer: Displacement of the -OH from the acid by -NH2- A. CH3COOH, HCl
- B. CH3COOH, PCl5
- C. CH3COOH, SOCl2
- D. Both 'B' and 'C'
Explanation: Both phosphorus pentachloride (PCI5) and thionyl chloride (SOCI2) are effective reagents for converting a carboxylic acid, like acetic…
Correct answer: Both 'B' and 'C'- A. Dehydrating agent and catalyst
- B. Hydrolyzing agent
- C. Dehydrating agent
- D. Catalyst
Explanation: Concentrated sulfuric acid serves two purposes in Fischer esterification.
Correct answer: Dehydrating agent and catalyst- A. Reaction of CH₃COOH with Na
- B. Reaction of CH₃COOH with NaHCO₃
- C. Reaction of CH₃COOH with Na₂CO₃
- D. Reaction of CH₃COOH with PCl₅
Explanation: The reaction of a carboxylic acid with PCI5 is a nucleophilic acyl substitution, not an acid-base reaction.
Correct answer: Reaction of CH₃COOH with PCl₅- A. 1
- B. 3
- C. 2
- D. 4
Explanation: Calcium is a Group 2 metal and forms a Ca2+ ion. To balance the charge of two acetate ions (CH3COO-), one calcium ion is needed.
Correct answer: 1- A. CI3CCOOH
- B. CICH2COOH
- C. Cl2CHCOOH
- D. CH3COOH
Explanation: The acidity of haloacetic acids is increased by the electron-withdrawing inductive effect of the halogen atoms.
Correct answer: CI3CCOOH- A. OH-
- B. RCOO-
- C. OR-
- D. PhO-
Explanation: The strength of a conjugate base is inversely proportional to the strength of its parent acid.
Correct answer: OH-- A. Salt
- B. Acid chloride
- C. Ester
- D. Amide
Explanation: The characteristic reaction of an acid is the donation of a proton. When a carboxylic acid reacts with a base to form a salt, the acidic…
Correct answer: Salt- A. Hydration
- B. Esterification
- C. Hydrolysis
- D. Salt formation
Explanation: Many artificial fruit flavors and aromas are due to the presence of specific esters.
Correct answer: Esterification- A. Banana
- B. Pineapple
- C. Apricot
- D. Jasmine
Explanation: The ester formed from the reaction of benzyl alcohol and acetic acid is benzyl acetate.
Correct answer: Jasmine- A. Cooling
- B. Heating
- C. Dehydration
- D. Both B and C
Explanation: Ammonium acetate is a salt that, when heated strongly, loses a molecule of water in a dehydration reaction to form acetamide.
Correct answer: Both B and C- A. Acetic acid
- B. Acetic anhydride
- C. Methanol
- D. Formic acid
Explanation: Aspirin (acetylsalicylic acid) is synthesized by the acetylation of the phenolic hydroxyl group of salicylic acid.
Correct answer: Acetic anhydride- A. -COOH
- B. -COOC
- C. -C=O
- D. None of these
Explanation: The correct answer is -COOH because it is the functional group that defines carboxylic acids. The other options.
Correct answer: -COOH- A. Acetic acid
- B. Ethane nitrile
- C. Acetic anhydride
- D. Acetamide
Explanation: Formation of Amide (Reaction with ammonia): Carboxylic acids react with ammonia to form ammonium salts which on heating produce acid…
Correct answer: Acetamide- A. Cis-trans isomers
- B. Structural isomers
- C. Metamers
- D. Position Isomers
Explanation: Maleic acid and fumaric acid are cis-trans (geometrical) isomers.They have the same molecular formula (C4H4O4) but differ in the…
Correct answer: Cis-trans isomers