CaO + 2 HClO₄ → Ca(ClO₄)₂ + H₂O

This is an acid-base reaction (neutralization): CaO is a base, HClO₄ is an acid.

Reactants:

• CaO – Calcium oxide
  • Other names: Quicklime , Burnt lime , Unslaked lime ... show morePebble lime , Calcia , Caustic lime , Calx , Calcium monoxide , Limestone , Burned lime , Lime , Quick lime show less
  • Appearance: White to pale yellow/brown powder ; White hygroscopic crystalline powder ; White or gray, odorless lumps or granular powder.
• HClO₄ – Chloric(VII) acid
  • Other names: Perchloric acid , Hyperchloric acid , Perchloric acid (72% solution) , Hydronium perchlorate
  • Appearance: Colorless liquid ; Colourless liquid with pungent odour

Products:

• Ca(ClO₄)₂ – Calcium perchlorate
  • Other names: Calcium perchlorate tetrahydrate , Calcium diperchlorate , Perchloric acid calcium salt (2:1) , Hydrated
  • Appearance: White to yellow crystalline solid
• 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