Organic Chemistry Questions and Answers – Reagents in Organic Chemistry

This set of Tough Organic Chemistry Questions and Answers focuses on “Reagents in Organic Chemistry”.

1. Which is the suitable catalyst for bringing out the transformation given below?

a) BF₃. Et₂0
b) NaOEt
c) tungsten lamp
d) dibenzoyl peroxide
View Answer

2. Which of the will give effective reduction of 3-hexyne to trans-3-hexene?
a) H₂/Lindlar’s catalyst
b) Na/liq. NH₃
c) Fe/NaCl
d) DIBAL
View Answer

Answer: b
Explanation: Na/liq. NH₃ will give an effective reduction for the following case:

3. Which of the reagent will give effective transformation of given compounds?

a) CH₂N₂
b) CH₃Li
c) (CH₃)₂CuLi
d) Ph₃P = CH₂
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4. Which is the mildest reducing agent which reduces only carbonyl group in presence of nitro, carboxyl, double bond and ester groups?
a) LiAIH₄
b) Na-NH₃
c) NaBH₄
d) H₂-Ni
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5. What will be the product for the given reactant and reagents?

a)
b)
c)
d)
View Answer

Answer: c
Explanation: LiAlH₄ will reduce double bond into single bond and aldehyde group into alcohol.

6. Which is the correct combination of reagent which can carry out following conversion?

a) (i) CH₃ – MgBr then H⁺ (ii) H₂S0₄ / ∆ (iii) NH₂ – NH₂ / KOH
b) (i) (CH₃)₂ CuLi then H⁺ (ii) NaBH₄ EtOH (iii) H₂S0₄ / ∆
c) (i) CH₃ – Li, then H⁺ (ii) PCC / ∆
d) (i) NaBH₄ ∙ CeCl₃ then H⁺ (ii) MnO₂ (iii) CH₃ – Li
View Answer

Answer: c
Explanation: Here CH₃ will attack at C=O and dehydration will take pass and again water will attack at meta position as a nucleophile at the ring. PCC will covert -OH into = O.

7. How acetophenone can be converted to phenol by reaction?
a) m-CPBA followed by base catalysed hydrolysis
b) conc. HN0₃
c) iodine and NaOH
d) Singlet oxygen followed by base catalysed hydrolysis product
View Answer

Answer: a
Explanation:

m-CPBA can convert ketone into amide and after ester hydrolysis it is reduced into phenol.

8. How can we prepare RR’ R” OH by the action of excess of a suitable Grignard reagent on which of the following reactants?
a) nitrile or an aldehyde
b) ester or an alcohol
c) aldehyde or a ketone
d) ketone or an ester
View Answer

Answer: a
Explanation: Preparation of 3^o alcohol from ketone and ester by the action of excess of a suitable Grignard reagent is carried out as shown below:

9. What is used to carry out the following conversion?

a) hydroboration oxidation followed by Jones oxidation
b) Wacker oxidation followed by haloform reaction
c) oxymercuration-determination followed by Jones oxidation
d) ozonolysis followed by haloform reaction
View Answer

Answer: b
Explanation: The transformation of a terminal or 1,2-disubstituted alkene to a ketone through the action of catalytic palladium(II), water, and a co-oxidant. Because of the ease with which terminal alkenes may be prepared and the versatility of the methyl ketone group installed by the reaction, the Wacker oxidation has been employed extensively in organic synthesis. This is followed by haloform reaction.

10. How many isomers of C₄H₈O when reacts with CH₃MgBr followed by acidification to alcohol (only consider carbonyl isomers and Including stereoisomers)?
a) 2
b) 3
c) 4
d) 5
View Answer

Answer: a
Explanation:

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