Question

1. Name the catalyst which helps in the conversion of sulphur dioxide to sulphur trioxide in step C.
2. In the contact process for the manufacture of sulphuric acid, sulphur trioxide is not converted to sulphuric acid by reacting it with water. Instead a two-step procedure is used. Write the equations for the two steps involved in D.
3. What type of substance will liberate sulphur dioxide from sodium sulphite in step E?
4. Write the equation for the reaction by which sulphur dioxide is converted to sodium sulphite in step F.

Answer 1

1. The catalyst that helps in the conversion of sulphur dioxide to sulphur trioxide in step C is Vanadium pentoxide.
2. The two steps for the conversion of sulphur trioxide to sulphuric acid are:
   1. \[\ce{SO3 + H2SO4 -> H2S2O7}\]
   2. \[\ce{H2S2O7 + H2O -> 2H2SO4}\]
3. The substance that will liberate sulphur dioxide in step E is dilute sulphuric acid \[\ce{H2SO4}\].
4. The equation for the reaction by which sulphur dioxide is converted to sodium sulphite in step F is:
   1. \[\ce{SO2 + 2NaOH -> Na2SO3 + H2O}\]
   2. \[\ce{Na2O + SO2 -> Na2SO3}\]