Name the anion [negative ion] present in the following compound:
Compound D when warmed with dilute H2SO4 give a gas which turns acidified potassium dichromate solution green.
Sulphite or bisulphite anions react with dilute sulphuric acid to give sulphur dioxide gas, which turns acidified potassium dichromate (K2Cr2O7) solution green.
M2SO3 + H2SO4 → M2SO4 + H2O + SO2
2MHSO3 + H2SO4 → M2SO4 +2H2O + 2SO2