All Free Biology MCQs with Answers
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19844 questions · page 515 of 1985
5141. Which of the following compounds would react readily with NaOH?
- A. R - NH2
- B. R- COCI
- C. RCOOH
- D. RCH2 -- OH
Explanation: Carboxylic acids readily react with bases like NaOH to form salts (carboxylate salts) and water through acid-base neutralization reactions.
Correct answer: RCOOH5142. in the following carboxylic acids
- A. Option A
- B. Option B
- C. Option C
- D. Option D
Explanation: Explanation for this question will be added soon!
Correct answer: Option D5143. Which of the following carboxylic acids is prepared by acid hydrolysis of ethane nitrile?
- A. Methanoic acid
- B. Ethanoic acid
- C. Propanoic acid
- D. Butanoic acid
Explanation: Ethanoic acid is indeed prepared by the acid hydrolysis of ethane nitrile (acetonitrile). This process involves the hydrolysis of the nitrile functional group (-CN) in acetonitrile to yield acetic acid.
Correct answer: Ethanoic acid5144. Consider the following structure of carboxylic acid:CH3 - CH -CH2 -CH -COOHCH3 CH3The correct name of the above structure according to IUPAC is:
- A. 2, 4-Dimethylpentanoic acid
- B. 4, 2-Dimethylpentanoic acid
- C. 2, 3-Dimethylpentanoic acid
- D. 4, 3-Dimethylpentanoic acid
Explanation: Option A is correct because it accurately describes the positions of the two methyl groups on the pentanoic acid chain.
Correct answer: 2, 4-Dimethylpentanoic acid5145. Reaction of ethanoic acid with ammonia gives:
- A. Ethanamide
- B. Ethanenitrile
- C. Ethylamine
- D. Nitromethane
Explanation: This is the correct product of the reaction between ethanoic acid and ammonia. The -COOH group of ethanoic acid reacts with NH3 to form -CONH2 group in ethanamide.
Correct answer: Ethanamide5146. Which of the following derivatives of carboxylic acid is the most reactive?
- A. Acid amide
- B. Acid halide
- C. Ester
- D. Acid anhydrid
Explanation: The most reactive derivative of carboxylic acid among the options provided is acid halide.
Correct answer: Acid halide5147. In which of the following reactions acid chloride produces aldehyde?
- A. Reaction with H2
- B. Reaction with NH3
- C. Hydrolysis
- D. Reaction With alcohol
Explanation: When an acid chloride reacts with hydrogen gas (H2) in the presence of a suitable catalyst, such as palladium or platinum, it undergoes reduction to form an aldehyde. This process involves the addition of hydrogen across the carbonyl group, leading to the conversion of the acid chloride into an aldehyde.
Correct answer: Reaction with H25148. Which of the following derivatives of carboxylic acid is least reactive?
- A. Acid halide
- B. Acid amide
- C. Ester
- D. Acid anhydride
Explanation: Acid amides are the least reactive among the given derivatives of carboxylic acids. This is because amides have a resonance structure that stabilizes the carbonyl group, making them less susceptible to nucleophilic attack compared to other derivatives.
Correct answer: Acid amide5149. When-COOH is attached directly to the beanzene ring the acid is called:
- A. Aliphatic
- B. Carboxylic
- C. Alicyclic
- D. Aromatic
Explanation: When -COOH (carboxyl group) is attached directly to the benzene ring, it forms benzoic acid, which is an example of an aromatic compound. Aromatic compounds are characterized by having conjugated double bonds and obeying Huckel's rule, which benzene and its derivatives (such as benzoic acid) do.
Correct answer: Aromatic5150. Consider the following sequence of conversion of X Into Y and Y into Z. Identify which of the following is Z:
- A. CH3COOCH3
- B. HCOOCH3
- C. CH3COOC2H5
- D. CH3COOH
Explanation: In first step, hydration of alkynes occur that produces acetaldehyde. In next step, oxidation of acetaldehyde produces acetic acid. In last step acetic acid reacts with ethanol to produce methyl acetate.
Correct answer: CH3COOCH3