The correct answer is Sodium hydrogen carbonate.Concept:Baking soda:The chemical name of baking soda is sodium hydrogen carbonate (NaHCO3).It is a mild non-corrosive basic salt.Explanation:Preparation of Baking Soda: It is produced through the Solvay process by using sodium chloride, sodium chloride, water, and carbon dioxide as raw materials.NaCl + H2O + CO2 + NH3 ? NH4Cl + NaHCO3 (Ammonium chloride) (Sodium hydrogen carbonate)On heating Sodium hydrogen carbonate, the following reaction takes place:2NaHCO3 + heat ? Na2 CO3 + H2O + CO2 Na2 CO3 is used to make washing soda that is used in the soap industry. Uses of baking soda:Baking soda undergoes a reaction with mild edible acid such as tartaric acid to manufacture baking powder.NaHCO3 + H+ ? CO2 + H2O + Sodium salt of acid (From any acid)This carbon dioxide produced makes bread or cake rise thereby making them soft and spongy.Being alkaline it is also an active ingredient in antacids that acts by neutralizing the excess acid produced in the stomach.It is also used in soda-acid fire extinguishers.Thus, the compound Z is baking soda i.e., sodium hydrogen carbonate.