Question

Calculate the weight proportion of H2O in Na2S2O2.5H2O?

Answer 1

Are you sure you don't mean `"sodium thiosulfate pentahydrate"`, i.e. `Na_2S_2O_3`? I make `"percentage water"` approx. `60%`.

Explanation:

We can calculate the percentage of water BY mass in `Na_2S_2O_3*5H_2O`....

i.e. `="Mass of water"/"Mass of hydrate"=(5xx18.01*g*mol^-1)/(158.11 *g*mol^-1)xx100%`

`=??%`

Just in regard to `S_2O_3^(2-)`, I have always liked to imagine this as `SO_4^(2-)` where ONE of the oxides has been replaced by sulfide ion, the which assumes the SAME oxidation number as oxide, and thus we gots `S(VI+)` and `S(-II)`, an AVERAGE oxidation state of `S(+II)`.