Answer :
Let's evaluate each statement one by one:
If a ketone reacts with a Grignard reagent, a tertiary alcohol is obtained.
- This statement is True. When a ketone reacts with a Grignard reagent (RMgX), the carbonyl carbon of the ketone gets attacked by the alkyl group of the Grignard reagent. This nucleophilic addition results in the formation of an intermediate that, upon hydrolysis, gives a tertiary alcohol. For example, if you react acetone (8C(=O)CH_3) with methylmagnesium bromide (8CH_3MgBr), the product will be 2-methyl-2-propanol, a tertiary alcohol.
Grignard reagents can be prepared using ethanol as the solvent.
- This statement is False. Grignard reagents are highly reactive and react with protic solvents like ethanol. Ethanol contains an 8OH group, which would readily react with the Grignard reagent, destroying it. Instead, Grignard reagents are typically prepared in anhydrous ether solvents, like diethyl ether or tetrahydrofuran (THF), which do not interfere with the reaction.
Grignard reagents are prepared by reaction of an alkyl or aryl halide with magnesium.
- This statement is True. Grignard reagents are indeed prepared by reacting an alkyl or aryl halide with magnesium metal. The typical process involves adding the halide to magnesium turnings in an anhydrous ether solvent to form the organomagnesium compound known as a Grignard reagent.
I hope this helps clarify your understanding of Grignard reagents and their reactions!
