" In contact process,the impurities of arsenic are removed by "

In contact process impurities of arsenic are removed by

In Contact process impurities of arsenic are removed by:

In contact process impurities of arsenic is removed by

In contact process inpurities of arsenic is removed by

Explain the following giving suitable reasons: In the manufacture of H_2SO_4 by contact process: The impurity of arsenic oxide must be removed before passing the mixture of SO_2 and air through the catalytic chamber.