1 | Appearance | White powder. | White or almost white powder. |
2 | Solubility | Passes | Freely soluble in water, Insoluble in alcohol. |
3 | Identification A (By Chemical test) | Complies | Solution should slightly alkaline. |
4 | Identification B (sulfate) | Complies | A white precipitate should form. |
5 | Identification C (Sodium) | Complies | A dense white precipitate should form. |
6 | Identification D (By Assay) | 97.3% | 95.0% to 100.5% |
7 | Appearance of solution | Passes | Clear and colourless solution. |
8 | Thiosulphate(S2O3) | Less than 0.1% | 0.1% max |
9 | Iron(Fe) | Less than 10 ppm | 10ppm max |
10 | Selenium (Se) | Less than 10ppm | 10ppm max |
11 | Zinc (Zn) | Less than 25ppm | 25ppm max |
12 | Assay | 97.3% | 95.0% to 100.5% of Na2SO3 |