Let C.M. be at a distance x Å from H-atom

Distance of C.M. from Cl atom

=(1.27–x)Å

Let the mass of H-atom = m units

The mass of the Cl-atom = 35.5 m units

If C.M. is taken at the origin, then

mx+(1.27–x)35.5m=0 mx=–(1.27–x)35.5m Negative sign indicatesthat if Cl atom is on the right side of C.M.(+), the hydrogen atom is on the left side of C.M. So, avoiding, if we get

x+35.5x=1.27×35.5 36.5x=45.085 x==1.235Å Therefore, the centre of mass located on theline joining H and Cl nuclei at a distance of 1.24 Å from the H atom.