Answer :
Final answer:
The Grignard reagent formation starts slowly due to the magnesium surface being coated with an oxide layer. Once this layer is removed, the reaction with 1-bromobutane proceeds rapidly due to the high reactivity of magnesium. Steric hindrance and instability at room temperature are not the reasons for the slow start. So the correct option is c) The Grignard reagent is unstable at room temperature.
Explanation:
The formation of the Grignard reagent does not start immediately upon the addition of 1-bromobutane to the magnesium turnings because magnesium surface is usually coated with an oxide layer which must be removed first. This is typically referred to as the induction period.So the correct option is c) The Grignard reagent is unstable at room temperature. Once the oxide layer is removed, exposing the reactive magnesium metal to the organic halide, the reaction proceeds very rapidly due to the high reactivity of the clean magnesium surface with 1-bromobutane.The initial delay is not related to steric hindrance or instability of the Grignard reagent at room temperature. Instead, reactivity is improved by using diethyl ether or tetrahydrofuran (THF) which stabilizes the Grignard reagent by forming a complex with the magnesium. Once the reaction is initiated, it can become highly exothermic. To maintain control over the reaction, especially when adding Grignard reagents to carbonyl compounds, various techniques such as inverse addition or transmetallation can be utilized to improve selectivity and reduce side reactions.
