Unit 17: Organic Compounds Containing Oxygen — Online MCQ Test
CHEMISTRY · NEET (All) · NEET
Practice Unit 17: Organic Compounds Containing Oxygen with a free chapter-wise online MCQ test.
This chapter covers: General methods of preparation properties reactions and uses. ALCOHOLS PHENOLS AND ETHERS Alcohols: Identification of primary secondary and tertiary alcohols: mechanism of dehydrat....
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Unit 17: Organic Compounds Containing Oxygen — Important Questions & Answers
Anisole on cleavage with HI gives:
- A. Iodobenzene and methanol
- B. Phenol and ethyl iodide
- C. Phenol and ethanol
- D. Phenol and methyl iodide
Answer: D. Phenol and methyl iodide
Cleavage of anisole (methoxybenzene) with HI yields phenol and methyl iodide (CH3I) due to the formation of stable phenoxide resonance and methyl carbocation/substitution.
Cleavage of anisole (methoxybenzene) with HI yields phenol and methyl iodide (CH3I) due to the formation of stable phenoxide resonance and methyl carbocation/substitution.
Reaction between acetone and methylmagnesium chloride followed by hydrolysis will give:
- A. Sec. butyl alcohol
- B. Tert. butyl alcohol
- C. Isobutyl alcohol
- D. n-butyl alcohol
Answer: B. Tert. butyl alcohol
Acetone (CH3COCH3) reacting with CH3MgCl (Grignard reagent) followed by hydrolysis gives tert-butyl alcohol (2-methylpropan-2-ol).
Acetone (CH3COCH3) reacting with CH3MgCl (Grignard reagent) followed by hydrolysis gives tert-butyl alcohol (2-methylpropan-2-ol).
The reaction of an alkoxide with an alkyl halide (e.g., Na+O-R + R'-X → R-O-R' + NaX) can be classified as:
- A. Alcohol formation reaction
- B. Dehydration reaction
- C. Williamson alcohol synthesis reaction
- D. Williamson ether synthesis reaction
Answer: D. Williamson ether synthesis reaction
The reaction of a sodium alkoxide with an alkyl halide to form an ether is known as the Williamson ether synthesis.
The reaction of a sodium alkoxide with an alkyl halide to form an ether is known as the Williamson ether synthesis.
Which of the following reagents would distinguish cis-cyclopenta-1, 2-diol from the trans-isomer?
- A. Ozone
- B. MnO2
- C. Aluminium isopropoxide
- D. Acetone
Answer: D. Acetone
Acetone reacts with cis-1,2-diols to form a cyclic acetonide (a five-membered ring), whereas the trans-isomer cannot form this strained structure.
Acetone reacts with cis-1,2-diols to form a cyclic acetonide (a five-membered ring), whereas the trans-isomer cannot form this strained structure.
The product formed by the reaction of an aldehyde with a primary amine is :
- A. Ketone
- B. Carboxylic acid
- C. Aromatic acid
- D. Schiff base
Answer: D. Schiff base
Reaction of a carbonyl compound (aldehyde or ketone) with a primary amine yields an imine, commonly known as a Schiff base, through a nucleophilic addition-elimination mechanism.
Reaction of a carbonyl compound (aldehyde or ketone) with a primary amine yields an imine, commonly known as a Schiff base, through a nucleophilic addition-elimination mechanism.
Which one of the following alcohols reacts instantaneously with Lucas reagent?
- A. CH3CH(OH)CH3
- B. (CH3)3COH
- C. CH3CH2CH2CH2OH
- D. CH3CH2CH(OH)CH3
Answer: B. (CH3)3COH
Lucas reagent gives immediate turbidity with tertiary alcohols. (CH3)3COH is a tertiary alcohol.
Lucas reagent gives immediate turbidity with tertiary alcohols. (CH3)3COH is a tertiary alcohol.
Given below are two statements: Statement I: The boiling point of three isomeric pentanes follows the order: n-pentane > isopentane > neopentane Statement II: When branching increases, the molecule attains a shape of sphere. This results in smaller surface area for contact, due to which the intermolecular forces between the spherical molecules are weak, thereby lowering the boiling point. In the light of the above statements, choose the most appropriate answer from the options given below:
- A. Statement I is correct but Statement II is incorrect.
- B. Statement I is incorrect but Statement II is correct.
- C. Both Statement I and Statement II are correct.
- D. Both Statement I and Statement II are incorrect.
Answer: C. Both Statement I and Statement II are correct.
Branching decreases surface area and weakens van der Waals forces, so boiling point decreases in the order n-pentane > isopentane > neopentane. Both statements are correct.
Branching decreases surface area and weakens van der Waals forces, so boiling point decreases in the order n-pentane > isopentane > neopentane. Both statements are correct.
Identify the major product C formed in the following reaction sequence: CH3CH2CH2I --(NaCN)--> A --(Partial hydrolysis / Br2, NaOH)--> B --> C Choose the correct option:
- A. butanamide
- B. α-bromobutanoic acid
- C. propylamine
- D. butylamine
Answer: D. butylamine
1-Iodopropane undergoes SN2 substitution with NaCN to form butanenitrile. Partial hydrolysis gives butanamide, and subsequent Hofmann bromamide reaction with Br2/NaOH converts the amide to propylamine (one carbon less). The intended major product after the complete sequence is propylamine.
1-Iodopropane undergoes SN2 substitution with NaCN to form butanenitrile. Partial hydrolysis gives butanamide, and subsequent Hofmann bromamide reaction with Br2/NaOH converts the amide to propylamine (one carbon less). The intended major product after the complete sequence is propylamine.
Lecithin, a small molecular weight organic compound found in living tissues, is an example of:
- A. Glycerides
- B. Carbohydrates
- C. Amino acids
- D. Phospholipids
Answer: D. Phospholipids
Lecithin is phosphatidylcholine, a phospholipid found in biological membranes.
Lecithin is phosphatidylcholine, a phospholipid found in biological membranes.
The product formed by the reaction of an aldehyde with a primary amine is :-
- A. Schiff base
- B. Ketone
- C. Carboxylic acid
- D. Aromatic acid
Answer: A. Schiff base
Aldehydes react with primary amines to form imines, which are commonly known as Schiff bases.
Aldehydes react with primary amines to form imines, which are commonly known as Schiff bases.