Organic Chemistry Multiple Choice Questions and Answers

(1) Alkyl halides can be converted into Grignard reagents by _______________

[A] Boiling them with Mg ribbon in alcoholic solution

[B] Warming them with magnesium powder in dry ether

[C] Refluxing them with MgCl₂ solution

[D] Warming them with Mgcl₂

Answer: Warming them with magnesium powder in dry ether

(2) Which is not present in Grignard reagent?

[A] Methyl group

[B] Magnesium

[C] Halogen

[D] −COOH group

Answer: −COOH group

(3) Which of the following compounds does not give a tertiary alcohol upon reaction with methylmagnesium bromide?

[A] 3-methylpentanal

[B] Ethyl benzoate

[C] 4,4-dimethylcyclohexanone

[D] 4-heptanone

Answer: 4-heptanone

(4) Which of the following statements about Grignard reagent is false?

[A] Grignard reagents (RMgBr) add to the carbonyl group of aldehydes and ketones

[B] An organosodium compound is not very reactive compared to a Grignard reagent

[C] Grignard reagents are prepared in ether or tetrahydrofuran (THF)

[D] Grignard reagents are decomposed by water and alcohol

Answer: An organosodium compound is not very reactive compared to a Grignard reagent

(5) Which of the following compounds gives a secondary alcohol upon reaction with methylmagnesium bromide?

[A] Butyl formate

[B] 3- pentanone

[C] Pentanal

[D] Methyl butanoate

Answer: Pentanal

(6) A Grignard’s reagent may be made by reacting magnesium with which of the following compound?

[A] Methyl amine

[B] Diethyl ether

[C] Ethyl iodide

[D] Ethyl alcohol

Answer: Ethyl iodide

(7) Which of the following compounds gives a primary alcohol upon reaction with phenylmagnesium bromide?

[A] 2-methyloxirane

[B] ethylene oxide

[C] ethyl formate

[D] carbon dioxide

Answer: ethylene oxide

(8) Which of the following reagents, when treated with phenylmagnesiuim bromide followed by acid workup, will yield 2-phenylethanol?

[A] Ethanol

[B] Diethyl ether

[C] Ethanal

[D] Oxirane

Answer: Oxirane

(9) Which of the following compounds would not give tert-butyl alcohol when treated with excess methylmagnesium bromide?

[A] acetyl chloride

[B] acetaldehyde

[C] methyl acetate

[D] acetic anhydride

Answer: acetaldehyde

(10) Which of the following reaction sequence that will best carry out the following preparation?

[A] a) i I + MeONa + CH₃H₂Br ii) neutralize

[B] b) i) I + EtONa ii) CH₃CH₂Br iii) neutralize

[C] c) i) CH₃CH₂Br + Mg, Et₂O ii) Add I iii) neutralize

[D] d) i) I + CH₃CH₂OH + Mg ii) neutralize

Answer: c) i) CH₃CH₂Br + Mg, Et₂O ii) Add I iii) neutralize

Organic Chemistry Questions and Answers – Grignard Reagent | Organic Chemistry Multiple Choice Questions and Answers

Download PDF