Potassium Biiodate is a primary standard substance that can be used as a basimetric as well as an oxidimetric standard. In addition to its versatility, it has the advantage of a high equivalent weight, especially when used to standardize bases. Its disadvantages are that it is relatively expensive, and only sparingly and slowly soluble in water. The reaction for its use as an oxidimetric standard is as follows:KH(IO3)2 + 11 H+ + 10 I- ? 6 I2 + K+ + 6 H2O.