Arrange the following compounds in decreasing order of their reactivity towards nucleophilic addition with methylmagnesium bromide ( CH₃MgBr ): (I) (II) (III)

Step-by-step solution

The reactivity of carbonyl compounds towards nucleophilic addition depends on the electrophilicity of the carbonyl carbon and the steric hindrance around it. In formaldehyde (I), the carbonyl carbon is bonded to two hydrogen atoms. It has the least steric hindrance and no electron-donating alkyl groups, making the carbonyl carbon highly electrophilic. Thus, it is the most reactive. In acetaldehyde (II), the carbonyl carbon is bonded to one methyl group and one hydrogen atom. The methyl group exerts a +I effect, whi