SO2 can act as an oxidising agent as well as a reducing agent but SO3 can act as oxidising agent only. why?
KIndly refer to the following link:
https://www.meritnation.com/ask-answer/question/why-so2-can-act-as-both-oxidizing-as-well-as-reducing-agent/chemistry/6790095
In SO3 the oxidation state of sulphur is +6 (Maximum attainable oxidation state) so it can only gain electrons to attain +4 and -2 oxidation state but it can not lose electrons. Therefore, SO3 act as an oxidising agent only.
https://www.meritnation.com/ask-answer/question/why-so2-can-act-as-both-oxidizing-as-well-as-reducing-agent/chemistry/6790095
In SO3 the oxidation state of sulphur is +6 (Maximum attainable oxidation state) so it can only gain electrons to attain +4 and -2 oxidation state but it can not lose electrons. Therefore, SO3 act as an oxidising agent only.