2 NaOH (aq) + CO₂ (g) → Na₂CO₃ (aq) + H₂O (l)

This is an acid-base reaction (neutralization): NaOH is a base, CO₂ is an acid.

Reactants:

• NaOH
  • Names: Sodium hydroxide , Caustic soda , Lye ... show moreSoda lye , Sodium hydrate , NaOH , White caustic , Lye [Sodium hydroxide] show less
  • Appearance: White, waxy, opaque crystals ; White hygroscopic solid in various forms ; Colorless to white, odorless solid (flakes, beads, granular form).
• CO₂
  • Names: Carbon dioxide , {{plainlist| , CO2 ... show moreCarbonic acid gas , Dry ice , [CO2] , Carbonic anhydride , R-744 , E-290 , E 290 , E290 , Carbonic acid anhydride , Carbon-12 dioxide , Methanedione , Carbon oxide , CO₂ , [Note: Normal constituent of air (about 300 ppm)]. show less
  • Appearance: Colorless gas ; Odourless colourless compressed liquefied gas ; Colorless, odorless gas. [Note: Shipped as a liquefied compressed gas. Solid form is utilized as dry ice.]

Products:

• Na₂CO₃ – Sodium carbonate
  • Other names: Soda ash , Washing soda , Soda crystals ... show moreSodium carbonate (anhydrous) , Na2CO3 , Disodium carbonate , Natriumkarbonat , Carbonic acid sodium salt (1:2) , Anhydrous sodium carbonate , Carbonic acid, disodium salt , Sodium carbonate, anhydrous , Soda-ash , Natrum carbonicum , Sodium carbonate anhydrous , Sodium salt of carbonic acid , Carbonic acid disodium salt show less
  • Appearance: White solid, hygroscopic ; White hygroscopic powder
• H₂O – Water, oxidane
  • Other names: Water (H2O) , Hydrogen hydroxide (HH or HOH) , Hydrogen oxide ... show moreDihydrogen monoxide (DHMO) (systematic name) , Hydrogen monoxide , Dihydrogen oxide , Hydric acid , Hydrohydroxic acid , Hydroxic acid , Hydrol , Μ-oxido dihydrogen , Κ1-hydroxyl hydrogen(0) show less
  • Appearance: White crystalline solid, almost colorless liquid with a hint of blue, colorless gas