Equivalent weight of Se₂Cl₂ when it undergoes disproportionation is

Halides formed by 16^th group elements are….MF₆, MX₄, MX₂, M₂X₂;

Thermal stability…..F^->Cl^->Br^->I^- ;

MF₆…SF₆,SeF₆,TeF₆….Inert due to steric reasons….Gases….sp³d²(6 bp)….octahedral….SF₆….Insulator ;

SF₄…Gas….Fluorinating agent ; SeF₄…Liquid ; TeF₄…Solid ;

MX₄….See saw (or) distorted tetrahedral…sp³d(4 bp+ 1 lp) ;

SCl₄+4H₂O$\to$S(OH)₄+4HCl ;

S(OH)₄$\to$H₂SO₃+H₂O ;

MX₂…angular…sp³(2 bp+2 lp) ; SCl₂ and OF₂…102⁰ ;

M₂X₂….Non linear non planar molecule…open book structure…polar molecule;

2Se₂Cl₂$\to$SeCl₄+3Se ….Disproportionation ;

$$\begin{gathered} 2{\stackrel{+1}{\mathrm{Se}}}_2{\mathrm{Cl}}_2\to \stackrel{+4}{\mathrm{Se}}{\mathrm{Cl}}_4+\stackrel{0}{3\mathrm{Se} ;} \\ \mathrm{EW} \mathrm{of} {\mathrm{Se}}_2{\mathrm{Cl}}_2=\frac{\mathrm{M}}{\mathrm{Total} \mathrm{decrease} \mathrm{in} \mathrm{O}.\mathrm{S}}\left(\mathrm{as} \mathrm{oxidant}\right)+\frac{\mathrm{M}}{\mathrm{Total} \mathrm{inrease} \mathrm{in} \mathrm{O}.\mathrm{S}}\left(\mathrm{as} \mathrm{reductant}\right); \\ \mathrm{EW} \mathrm{of} {\mathrm{Se}}_2{\mathrm{Cl}}_2=\frac{\mathrm{M}}{\mathrm{Total} \mathrm{decrease} \mathrm{in} \mathrm{O}.\mathrm{S}}\left(\mathrm{as} \mathrm{oxidant}\right)+\frac{\mathrm{M}}{\mathrm{Total} \mathrm{inrease} \mathrm{in} \mathrm{O}.\mathrm{S}}\left(\mathrm{as} \mathrm{reductant}\right); \\ \mathrm{EW} \mathrm{of} {\mathrm{Se}}_2{\mathrm{Cl}}_2=\frac{\mathrm{M}}{2}\left(\mathrm{as} \mathrm{oxidant}\right)+\frac{\mathrm{M}}{6}\left(\mathrm{as} \mathrm{reductant}\right) ; \end{gathered}$$