Question

Preparation of Grignard reagent (2 points) Some organomagnesium halides (Grignard reagents) can be challenging to synthesize even when glass- ware is rigorously dried. Several improvements were developed to increase chances of successful gen- eration of organomagnesium halide. One method is to stir magnesium turnings vigorously under nitrogen atmosphere for several hours before adding alkyl or aryl halide. During that time the color Mg turnings darkens significantly (picture change from Silver to Space Gray in iPhone color pallette) of Explain the color change. plain why the reaction of organic halide with "Space Gray" magnesium is faster than with regular magnesium turnings.

Answer 1

the color change is due to the formation of MgO layer on the magnesium lead to colur change.

space gray magnesium is faster because the magnesium turnings are coated by MgO , such that leads to inactivation. where as the space gray magnesium conatns MgS which is highly active towards the alkyl halides