Select the correct statements regarding the products obtained when ${\mathrm{Na}}_2{\mathrm{S}}_2{\mathrm{O}}_3.5{\mathrm{H}}_2\mathrm{O}$ is subjected to strong heating.

(I) Disproportionation reaction takes place

(II) ${\mathrm{Na}}_2{\mathrm{SO}}_3$ and ${\mathrm{Na}}_2{\mathrm{S}}_5$are produced.

(III) ${\mathrm{Na}}_2{\mathrm{SO}}_4$ and ${\mathrm{Na}}_2{\mathrm{S}}_5$ are produced.

(IV) One of the products has zig-zag open chain structure.

Strong heating of sodium thiosulfate gives sodium sulfate and sodium polysulfide.

$4{\mathrm{Na}}_2{\mathrm{S}}_2{\mathrm{O}}_3.5{\mathrm{H}}_2\mathrm{O}\stackrel{∆}{\to }3{\mathrm{Na}}_2{\mathrm{SO}}_4+{\mathrm{Na}}_2{\mathrm{S}}_5+20{\mathrm{H}}_2\mathrm{O}$

Above reaction is disproportionation reaction because S is reduced when converted to N₂S₅ and oxidized when converted to Na₂SO₄

Na₂S₅ has ${\mathrm{S}}_5^{2-}$ ion that has a zig-zag structure.