Both Sulphite () and Carbonate () anions vigorously effervesce with dilute acid, yielding colorless — Qualitative and Quantitative Analysis Chemistry Question

💡 Solution & Explanation

Both yield gases ($SO_2$ and $CO_2$) that precipitate $CaCO_3$/$CaSO_3$ with lime water. However, only $SO_2$ acts as a reducing agent strong enough to turn orange acidified $K_2Cr_2O_7$ paper green (by reducing $Cr^{6+}$ to $Cr^{3+}$).