Dipolar moment between HI and HF [duplicate]








**This question already has answers here**:
 
 




[Does the dipole moment increase or decrease by increasing the bond length?](/questions/82884/does-the-dipole-moment-increase-or-decrease-by-increasing-the-bond-length)

 (2 answers)
 

Closed 5 years ago.



Which between $\ce{HI}$ and $\ce{HF}$ has a greater dipolar moment?
I think it is $\ce{HI}$ because the atomic radius of $\ce{I}$ is greater.




The dipole moment of $\ce{HF}$ is greater than $\ce{HI}$:


* $\ce{HF} = \pu{1.91 D}$
* $\ce{HI} = \pu{0.42 D}$


This is due to high electronegativity of fluorine. Hence from $\mu = \vec{q} \cdot \vec{d}$, the charge of fluorine is larger than iodine, but the bond length changes only a small amount. 


 2