The function of Fe(OH)3 in the contact process is

In the Contact process, arsenic oxide is a poison for the catalyst. It is removed when the gas is passed over ferric hydroxide.    The reaction is as follows:                                    As2​O3 ​+  2Fe(OH)3​  →  2FeAsO3​  +  3H2​OHence, the function of Fe(OH)3​ in the contact process is to remove arsenic impurities.