Which of the following statements are correct ?

Options

A. S-S bond is present in `H_(2)S_(2)O_(6)`
B. In peroxosulphuric acid `(H_(2)SO_(5))` sullphur is in +6 oxidation state
C. Iron powder along with `Al_(2)O_(3) and K_(2)O` is used as a catalyst in the preparation of `NH_(3)` by Haber's process
D. Changes in enthalpy is positive for the preparation of `SO_(3)` by catalytic oxidation of `SO_(2)`

Answer

A, B

Explanation

Iron oxide (not iron powder) `+Al_(2)O_(3) + K_(2)O` is used as a catalyst in Haber's process for manufacture of `NH_(3)`. Change of enthalpy is -ve (not + ve) for preparation of `SO_(3)` by catalytic oxidation of `SO_(2)`. There is S-S bond in `H_(2)S_(2)O_(6)`. Thus, options (a) and (b) are correct.