Qualitative analysis of the anionic part of a salt using it's soda extract
If a solution of $\ce{H2SO4}$ is added to a some carbonate, bicarbonate or sulfite, it will produce some $\ce{CO2}$ or $\ce{SO2}$ effervescence with gas bubbles filling the container where this test is done, and maybe cause it to overflow. With sodium bicarbonate the equation is :
$$\ce{H2SO4  + 2 NaHCO3 -&gt; Na2SO4 + 2 H2O + 2 CO2}$$
With sodium sulfite, it is :
$$\ce{Na2SO3 + H2SO4 -&gt; Na2SO4 + H2O + SO2}$$