As shown in Fig. suppose the H nucleus is located at the origin. Then,
x1 = 0, x2 = 1.27 Å, m1 = 1, m2 = 35.5
The position of the CM of HCl molecule is
Thus the CM of HCl is located on the line joining H and Cl nuclei at a distance of 1.235 Å from the H nucleus.