A student investigates the gaseous products of four different reaction mixtures. Which of the following reaction mixtures produces a gas that turns damp red litmus paper blue?
Heating solid (NH4)2SO4(\text{NH}_4)_2\text{SO}_4(NH4)2SO4 with warm aqueous NaOH\text{NaOH}NaOH
Adding dilute HCl\text{HCl}HCl to solid KHCO3\text{KHCO}_3KHCO3
Reacting Mg\text{Mg}Mg ribbon with dilute HCl\text{HCl}HCl
Adding concentrated H2SO4\text{H}_2\text{SO}_4H2SO4 to solid NaCl\text{NaCl}NaCl