# Why don't we consider the attached hydrogens in inductive effect?

Consider the molecule 1-chloroethane

Let carbon attached to $$\ce{Cl}$$ be $$\ce{C1}$$ and other one be $$\ce{C2}$$. While learning inductive effect I was told that $$\ce{Cl}$$ due to high electronegativity pulls the $$\ce{C1–Cl}$$ bond electrons towards itself leading to development of partial positive charge on $$\ce{C1}$$ and partial negative charge on $$\ce{Cl}$$ .Now this $$\ce{C1}$$ which has became a little electron-deficient tries to pull electron of the adjacent adjacent carbon $$\ce{C2}$$ leading to development of a further smaller partial charge on $$\ce{C2}$$. I have following doubts:

1. Will $$\ce{C1}$$ only pull electrons from $$\ce{C2}$$ or from the hydrogen atom attached to it also. I think it does pull, but then why don't we take that pull into consideration?

2. When $$\ce{C1}$$ pulls electrons from $$\ce{C2}$$, the partial positive charge developed on it due to the pull of electrons by the chlorine atom will be reduced a little but why do we then show $$\ce{C1}$$ to have same partial positive charge?

• Kindly see this and use mathjax again, Thanks! chemistry.meta.stackexchange.com/questions/86/… Jun 27 '21 at 5:40
• The effect exists but is very small and insignificant. Jun 27 '21 at 6:20
• Is not the inductive effect taken as the relative effect of atom/group, compared to hydrogen ? By other words, a bound hydrogen is taken as the reference zero by definition. Jun 27 '21 at 13:24
• @Poutnik do you mean the same as first line in the given link en.wikipedia.org/wiki/… Jun 27 '21 at 13:30
• @Lllt No, I want to say that inductive effect of the methyl group or the chlorine atom is compared to inductive effect of hydrogen, if it was there instead of them. Jun 27 '21 at 15:44

I will show you how I understand this effect. I like to think that partial positive charge on $$\ce{C1}$$ attracts the electrons from $$\ce{C2}$$ because of the electrostatic force. With this model your questions can be answered this way:
1. Yes, $$\ce{C1}$$ will pull electrons from every adjacent atom, including hydrogen. It may pull them, however, to less extent from hydrogen because it has less electrons than carbon (or rather alkyl group), and smaller charge will result in weaker attraction according to our model.
2. What you are saying is right. The reason why we still write just $$\delta +$$ instead of some kind of $$0.7\delta +$$ is mostly convenience. This writing can be used in organic chemistry to show mechanisms, for example, and in this case we don't need super-accuracy in determining the magnitude of the charge itself (like it could be in some physical model), we just need to show that it is positive. It will be different in every case (molecule) and calculating the exact charge seems like waste of time, but we still are aware of the inductive effect, although don't explicitly show it.
• @Lllt, it's the electrostatic force. The law is $F = k \ \frac{q_1 q_2}{r^2}$. Let's say that $q_1$ is the charge of $\ce{C1}$ carbon, the force now depends on the charge $q_2$. If there are more electrons around, this charge is greater, therefore the force is also greater. There are more electrons at the carbon (because it has another hydrogens from which to take them), so the force is greater. However, I don't think that this gives a huge difference between the carbon and hydrogen, and teachers should actually note the effect on hydrogen too. Jun 27 '21 at 8:21