Which of the following is correct ?
Aqueous solution of `Na_2S_2O_3` on reaction with `Cl_2` gives ?
(a) `Na_2S_4O_6`
(b) `NaHSO_4`
(c) `NaCl`
(d) `NaOH`
(ii) Acidic solution of `Na_(2)S_(2)S_(2)O_(3)` on reaction with `Cl_(2)` gives
(a) `Na_(2)S_(4)O_(6)`
(b) `NaHSO_(4)`
`NaSO_(4)`
(d) `NaOH`
(iii) Basic solution of `Na_(2)S_(2)O_(3)` on reaction with `Cl_(2)` gives
(a) `NaOH`
(b) `Na_(2)S_(4)O_(6)`
(c) `Na_(2)SO_(4)^(oplus)`
(d) `NaHSO_(4)`

Explanation

(a) Refer formulae and concepts, point 4 (c).
`S_2O_3^(2-)` in aqueous or neutral medium is oxidised to `HSO_4^(ɵ)` and `Cl_2` is reduced to `Cl^(ɵ)` or `Na_2S_2O_3+4Cl_2+5H_2Oto2NaHSO_4+8HCl`
(ii) (a) `S_(2)O_(3)^(2-)` in acidic medium is oxidised to `S_(4)O_(6)^(2-)` (tetrathionate ion), and `Cl_(2)` is reduced to `Cl^(ө)`
`{:(2S_(2)O_(3)^(2-) rarr S_(4)O_(6)^(2-)+2e^(-)),(Cl_(2)+2e^(-) rarr 2Cl^ɵ),(ulbar(2S_(2)O_(3)^(2-)+Cl_(2) rarr S_(4)O_(6)^(2-)+2Cl_ɵ)):}`
or `2Na_(2)S_(2)O_(3) +Cl_(2) rarr Na_(2)S_(4)O_(6) +2NaCl`
(iii) (c) `S_(2)O_(3)^(2-)` in basic medium is oxdised to `SO_(4)^(2-)`, and `Cl_(2)` is reduced to `Cl^ɵ`
`{:(10 oversetɵ(O)H+S_(2)O_(3)^(2-) rarr 2SO_(4)^(2-)+5H_(2)O+ cancel(8e^(-))),(cancel(2e^(-))+Cl_(2) rarr 2Cl^ɵ"]"xx 4),(ulbar(S_(2)O_(3)^(2-)+10 oversetɵ(O)H + 4Cl_(2) rarr 2SO_(4)^(2-)+8Cl^ɵ+5H_(2)O)),("or"),(Na_(2)S_(2)O_(3)+10 NaOH +4Cl_(2) rarr 2Na_(2)SO_(4)+8NaCl+5H):}`.