Find out the oxidation numbers of (i) S atoms in `Na_(2)S_(2)O_(3)` and CI atoms in bleaching powder `CaOCI_(2)`

Explanation

(i) oxidation number of S atoms in `Na_(2)S_(2)O_(3)`
(a) By conventional method `overset(+1)Na_(2) overset(x)S_(2) overset(-2)O_(3)` or ` 2xx(+1)+2x+3xx(-2)=0` or x=+2 (wrong)
but this is wrong because both the sulphur atoms cannot be in the same oxidation state as is evident from the fact that when `Na_(2)S_(2)O_(3)` is treated with dil `H_(2)SO_(4)` one S atom gets preciptated while the other gets converted in to `SO_(2)` the oxdation number of these two S atoms however be determined by the chemical bonding method
by chemical method the structure of `Na_(2)S_(2)O_(3)` is
`Na^(+)O-overset(S)overset(uparrow)underset(O)underset(||)S-O^(-)-Na^(+) "or" Na^(+)O-overset(S)overset(||)underset(O)underset(||)S-O^(-)Na^(+)`
since there is a coordinate bond between the two S atoms therefore the acceptors S atom has an O.N of -2 the O.N of the other S atom can be calculated as follows
(ii) oxidation number of chlorine in bleaching powder `CaOCI_(2)`
average O.N of CI in `CaOCI_(2)` is `overset(+2)Ca overset(-2)Ooverset(x)CI_(2)` or 2x+2-2=0 or x=0
(a) by stoichiometry the composition of bleaching powder is `Ca^(2+)(OCI)^(-)CI^(-)` here O.N of CI in `OCI^(-)` is +1 while that in `CI^(-)` is -1 and the average of two oxidation number =`1xx(+1)xx(-1)=0`