Which gas is evolved when sodium bicarbonate is heated? MCQ with Answer and Explanation

Explanation:
Sodium bicarbonate (NaHCO₃), baking soda, is a mild base that neutralizes excess stomach acid (HCl) providing relief from acidity. Reaction: NaHCO₃ + HCl → NaCl + H₂O + CO₂. It is a component of many antacid formulations. Sodium chloride is table salt, ammonium chloride is not safe, and calcium sulfate is plaster of Paris ingredient. Milk of magnesia (Mg(OH)₂) is also an antacid.

Explanation:
Salt is obtained by evaporation of seawater in shallow ponds. Water evaporates leaving salt behind. Filtration cannot separate dissolved salt. Distillation would give pure water, not salt. Sublimation for sublimable solids.

Explanation:
Distilled water is considered the purest form of water because it is obtained by boiling water and condensing the steam, leaving almost all impurities, minerals, and salts behind. Rainwater is relatively pure but dissolves atmospheric gases and dust as it falls.