In ${\mathrm{SCl}}_2$ the central atom Sulphur involves the hybridisation

we know that the electronic configuration of S atom is as follows: ${\mathrm{S}}_{\text{atom }}\to \left[\mathrm{Ne}\right]3{\mathrm{s}}^{2}3{\mathrm{p}}^4$

Now S in ${\mathrm{SCl}}_2$ has two electrons in s 3s and four in 3p shells 

Thus. In ${\mathrm{SCl}}_2$ the central atom Sulphur involves the hybridisation $s{p}^3$