Question

Inductive effect is the partial shifting of the sigma-bonding electrons towards more EN (take as electronegativity or electronegative in this text) atom so why we will say that alkyl groups will always show +I effect.

For the case of boron (EN 2.05) and carbon (EN 2.55), will the alkyl group show +I or -I effect?

Answer 1

Alkyl groups generally demonstrate a +I effect because carbon is less electronegative than hydrogen, pushing electrons towards the latter. If an alkyl group is attached to a boron atom, which is less electronegative than carbon, the alkyl group will display a -I effect.

Step-by-step explanation:

The inductive effect is a concept in organic chemistry where sigma-bonding electrons are displaced along a carbon chain. Alkyl groups are generally considered electron-donating groups because the carbon atoms within an alkyl group have a tendency to share their electrons with adjacent atoms.

The carbon atoms in alkyl groups are less electronegative than a hydrogen atom, so they tend to push electrons toward the hydrogen atom, showing a +I effect. However, when comparing a boron atom (EN 2.05) to a carbon atom (EN 2.55), the alkyl group attached to boron would show a -I effect because boron is less electronegative than carbon.