Final answer:
To start a Grignard reaction, magnesium is reacted with an alkyl or aryl halide in anhydrous diethyl ether. Indicators of a successful reaction include a cloudy solution, precipitate formation, heat generation, and a change in magnesium's appearance. Indicators like those in titration experiments are not used to monitor Grignard reactions.
Step-by-step explanation:
To start a Grignard reaction, the magnesium metal is typically reacted with an alkyl or aryl halide in a dry solvent, such as anhydrous diethyl ether. One of the major indicators that the reaction is going well is the formation of the Grignard reagent, which can be observed by the appearance of a cloudy solution or the presence of a precipitate. Sometimes, heat is generated as the reaction proceeds. Additionally, the consistency of the magnesium's surface turning dull from shiny indicates the initiation of the reaction. To ensure success, the reaction mixture should be free of moisture and oxygen.
It is important to note that while indicators are used in titration experiments to determine the equivalence point by changing color at certain levels of acidity or basicity, they are not typically used to monitor the Grignard reaction.