Q. As2O3 is insoluble in water but soluble in 10% NaOH solution. The solution of
As2O3 in NaOH is titrated against iodine (in presence of
NaHCO3 which does not react with iodine, but neutralises the
HI formed). The two steps are represented as:
As2O3+6NaOH→2Na3AsO3+3H2O
2Na3AsO3+2I2+2H3O→2Na3AsO4+4HI
The equivalent weight of As2O3 is (At. wt. of As=75):
