NaOH (caustic soda): One of the most widely produced industrial chemicals. Used in soap and detergent manufacture, paper industry (pulping), textile processing (mercerization of cotton), and as a drain cleaner. Produced by the Castner-Kellner cell or modern membrane cell chlor-alkali process.

$Na_{2}CO_{3}$ (washing soda / soda ash): Manufactured globally via the Solvay process. Used in glass manufacturing ($SiO_{2}$ + $Na_{2}CO_{3}$ → $Na_{2}SiO_{3}$), water softening (removes $Ca^{2+}$/$Mg^{2+}$ hardness), and as an alkaline cleaning agent in laundry.

$NaHCO_{3}$ (baking soda): Used as a leavening agent in baking (releases $CO_{2}$ when heated or acidified), as a mild antacid (neutralizes excess HCl in stomach), in fire extinguishers ($CO_{2}$ generation), and in effervescent tablets.

NaCl (common salt): Raw material for the entire chlor-alkali industry. Essential electrolyte in human physiology. Used as a food preservative (osmotic dehydration of microbes).

CaO (quicklime): Used in steel manufacturing (flux to remove impurities as slag), cement production, and soil treatment (neutralizes acidity). Produced from abundant limestone ($CaCO_{3}$).

Ca(OH)_{2} (slaked lime): Used in whitewashing buildings, manufacture of bleaching powder (Ca(OH)_{2} + $Cl_{2}$ → CaO$Cl_{2}$), treatment of acidic wastewater, and as a mortar ingredient in construction.

$CaCO_{3}$ (limestone/marble): Most widely used mineral in the world. Raw material for cement, lime, and glass. Marble is a metamorphic form of $CaCO_{3}$ used in sculpture and architecture.

$CaSO_{4}$·½$H_{2}O$ (Plaster of Paris): Used in orthopedic casts, dental molds, decorative moldings, and fire-resistant building boards. The slight expansion on setting ensures close fit in casts.

Portland cement: The binding material of modern construction. Contains $Ca_{2}SiO_{4}$, $Ca_{3}SiO_{5}$, $Ca_{3}Al_{2}O_{6}$. Gypsum ($CaSO_{4}$·2$H_{2}O$) added to control setting rate. Over 4 billion tonnes produced annually worldwide.

Mg alloys: Mg is the lightest structural metal; alloys with Al used in aircraft and automotive frames. Mg-based alloys (e.g., duralumin) offer high strength-to-weight ratio.

Li-ion batteries: Li is the anode material in rechargeable batteries due to its very low standard electrode potential (−3.04 V). Drives modern electronics, EVs, and energy storage.