$S{e}_{2}C{l}_2$ undergoes disproportionation to give two products X and Y. In one of the product Se is in zero oxidation state and in another product Se is in +4 oxidation state. If E is the Gram-equivalent weight in grams of $S{e}_{2}C{l}_2$ in the above reaction find the value of E:(Atomic wt.of Cl=35.5,Se=79)