Unit 11: Alcohols, Phenols and Ethers

21. Which of the following is used as a solvent in the preparation of ethers?

a) Methanol
b) Ethanol
c) Diethyl ether
d) Phenol
Answer: c) Diethyl ether

22. In the presence of concentrated sulfuric acid, which alcohol undergoes dehydration to form an alkene?

a) Ethanol
b) Propanol
c) Butanol
d) All of the above
Answer: d) All of the above

23. The reaction of an alcohol with a halogen acid (HX) to form an alkyl halide is known as:

a) Substitution reaction
b) Addition reaction
c) Elimination reaction
d) Oxidation reaction
Answer: a) Substitution reaction

24. In the preparation of phenol from benzene, which reagent is used?

a) Bromine water
b) Sodium hydroxide
c) Sulfuric acid
d) Sodium phenoxide
Answer: d) Sodium phenoxide

25. Which compound is known for its use in making artificial flavorings and fragrances?

a) Methanol
b) Ethanol
c) Phenol
d) Vanillin
Answer: d) Vanillin

26. Which type of alcohol is least likely to be oxidized?

a) Primary alcohol
b) Secondary alcohol
c) Tertiary alcohol
d) None of the above
Answer: c) Tertiary alcohol

27. The reaction of phenol with nitric acid yields:

a) Nitrobenzene
b) Mononitrophenol
c) Dinitrophenol
d) Trinitrophenol
Answer: b) Mononitrophenol

28. Which of the following statements about ethers is false?

a) Ethers have a general formula of R−O−R′R-O-R’R−O−R′
b) Ethers are generally less reactive than alcohols
c) Ethers can be hydrolyzed by strong acids
d) Ethers are highly soluble in water
Answer: d) Ethers are highly soluble in water

29. The formation of an ether from two alcohols is an example of which type of reaction?

a) Dehydration
b) Hydrolysis
c) Oxidation
d) Reduction
Answer: a) Dehydration

30. Which reagent is commonly used to oxidize primary alcohols to aldehydes?

a) Chromic acid
b) Sodium bicarbonate
c) Sodium chloride
d) Sodium hydroxide
Answer: a) Chromic acid