MgO + 2 HCl → MgCl₂ + H₂O

This is an acid-base reaction (neutralization): MgO is a base, HCl is an acid.

Reactants:

• MgO – Magnesium oxide
  • Other names: Magnesia , Periclase , Magnesium oxide fume ... show moreMgO , Magmitt , Calcined brucite , Calcined magnesia , Magnesia fume show less
  • Appearance: White powder ; Hygroscopic fine white powder ; Finely divided white particulate dispersed in air. [Note: Exposure may occur when magnesium is burned, thermally cut, or welded upon.]
• HCl – Chlorane , Hydrogen chloride
  • Other names: Hydrochloric acid , M , Uriatic acid ... show moreHydronium chloride , Chlorhydric Acid , Hydrochloric acid gas , HCl , Anhydrous hydrogen chloride , Hydrochloric acid, anhydrous , Aqueous hydrogen chloride , [Note: Often used in an aqueous solution.] show less
  • Appearance: Colorless, transparent liquid, fumes in air if concentrated ; Colorless gas ; Colourless compressed liquefied gas with pungent odour ; Colorless to slightly yellow gas with a pungent, irritating odor. [Note: Shipped as a liquefied compressed gas.]

Products:

• MgCl₂
  • Names: Magnesium chloride , Magnesium dichloride , Magnesium chloride anhydrous ... show moreMgCl2 , [MgCl2] show less
  • Appearance: White or colourless crystalline solid ; Deliquescent white solid in various forms
• 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