On using boiled HNO3 in comparing AgNO3 and KSCN solutions?

Question

a solution containing AgNO3, distilled water and recently boiled 6N HNO3 is titrated with KSCN solution (indicator is ferric alum). why is it necessary to use boiled HNO3?

Answer 1

Boiling HNO3 removes dissolved NO2.

This would complex with the Fe3+ ions.