The protons of methylene group between the two carbonyl groups in ethylacetoacetate are acidic in nature. When compounds containing such acidic protons are treated with bases the loose proton and form enolates.
In this particular example when ethylacetoacetate is reacted with methyl magnesium bromide, the methyl group abstracts the acidic proton and converts into
methane gas. The enolate when hydrolyzed is again converted into ethylacetoacetate as shown below,
When iron loses the 2 4s electrons, it attains a valency of +2. Sometimes, iron will also lose one of the paired electrons from 3d orbital, leaving the entire 3d orbital filled with unpaired electrons (which provides a more stable configuration). In this case, its valency will be +3.
Answer:
Carbon has six electrons (2 core and 4 valence), and can form four bonds with neighboring atoms. Nitrogen has seven electrons (2 core and 5 valence)(1s2, 2s2, 2px1, 2py1, 2pz1). So if you are following the rules, you might well assume that nitrogen would be able to form five bonds (after all, it has five valence electrons.)