In the HCl molecule, the separation between the nuclei of the two atoms is about 1.27A. Find the approximate location of the centre of mass of the molecule, given that the chlorine atom is about 35.5 times as massive as a hydrogen atom and nearly all the mass of an atom is concentrated in its nucleus.

Explanation

Given, `r=1.27A`
`m_H=1u,m_(cl)=35.5u`
`r_1((m_(cl))/(m_H+m_(cl)))r` and `r_2=((m_H)/(m_H+m_(cl)))r`
i.e `r_1=(35.5)/(36.5)xx1.27A` and `r_2=(1xx1.27A)/(36.5)`
`r_1=1.235A` and `r_2=0.03479A`
`:.` Centre of mass of the molecule is at 1.235 A from H and 0.035A from Cl atom.