question_answer 49)

  Oxidation of sulphur dioxide into sulphur trioxide in the absence of a catalyst is a slow process but this oxidation occurs easily in atmosphere. Explain how does this happen? Give chemical reactions for the conversion of \[S{{O}_{2}}\]into\[S{{O}_{3}}\].

Answer:

  The oxidation of sulphur dioxide into sulphur trioxide can occur both photo chemically or non-photo chemically. In the near ultraviolet region, the \[S{{O}_{2}}\] molecules react with ozone photo chemically.                                 \[S{{O}_{2}}+{{O}_{3}}\xrightarrow{hv}S{{O}_{3}}+{{O}_{2}}\]                                 \[2S{{O}_{2}}+{{O}_{2}}\xrightarrow{hv}2S{{O}_{3}}\] Non-photo chemically,\[S{{O}_{2}}\] may be oxidised by molecular oxygen in presence of dust and soot particles. \[2S{{O}_{2}}+{{O}_{2}}\xrightarrow{Particles}2S{{O}_{3}}\]