$\mathrm{HgCl}_2\gt\mathrm{SO}_3\gt\mathrm{SiCl}_4\gt\mathrm{NH}_3$
1. $\mathrm{HgCl}_2$ have linear geometry and have bond angle $180^{\circ}$.
2. $\mathrm{SO}_3$ have Trigonal planar geometry and have bond angle of $120^{\circ}$.
3. $\mathrm{SiCl}_4$ have Tetrahedral geometry and have bond angle of $109.5^{\circ}$.
4. $\mathrm{NH}_3$ have Trigonal pyramidal geometry and have bond angle of $107^{\circ}$.